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NOTICE OF INCORPORATION 

United States Legal Document 

J^" All citizens and residents are hereby advised that 
this is a legally binding document duly incorporated by 
reference and that failure to comply with such 
requirements as hereby detailed within may subject you 
to criminal or civil penalties under the law. Ignorance of 
the law shall not excuse noncompliance and it is the 
responsibility of the citizens to inform themselves as to 
the laws that are enacted in the United States of America 
and in the states and cities contained therein. "^& 

* * 

NFPA 54 (2006), National Fuel and Gas Code, 
as incorporated and mandated by the States 
and Municipalities, including Florida, Texas, 
Maryland, California, Utah, Oklahoma, et. 
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ANSI Z223.1 

An American National Standard 

2006 



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AGA 

American Gas Association 



IMPORTANT NOTICES AND DISCLAIMERS CONCERNING AGA and NFPA DOCUMENTS 

Notice and Disclaimer of Liability Concerning the Use of AGA and NFPA Documents 

NFPA codes, standards, recommended practices, and guides, of which the document contained herein is one, and 
AGA's Z223.1 are developed through a consensus standards development process approved by the American National 
Standards Institute. This process brings together volunteers representing varied viewpoints and interests to achieve con- 
sensus on fire and other safety issues. While the AGA and the NFPA administer the process and establish rules to pro- 
mote fairness in the development of consensus, they do not independently test, evaluate, or verify the accuracy of any 
information or the soundness of any judgments contained in their codes and standards. 

The AGA and the NFPA disclaim liability for any personal injury, property or other damages of any nature whatso- 
ever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use 
of, or reliance on this document. The AGA and the NFPA also make no guaranty or warranty as to the accuracy or com- 
pleteness of any information published herein. 

In issuing and making this document available, the AGA and the NFPA are not undertaking to render professional or 
other services for or on behalf of any person or entity. Nor are the AGA and the NFPA\indertaking to perform any duty 
owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent 
judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care 
in any given circumstances. 

The AGA and the NFPA have no power, nor do they undertake, to police or enforce compliance with the contents of 
this document. Nor do the AGA and the NFPA list, certify, test, or inspect products, designs, or installations for compli- 
ance with this document. Any certification or other statement of compliance with the requirements of this document 
shall not be attributable to the AGA and the NFPA and is solely the responsibility of the certifier or maker of the state- 
ment. 

(Important Notices and Disclaimers continued on inside back cover.) 



8/05 



ANSI Z223. 1-1 54-1 



Copyright © 2005, by the National Fire Protection Association and the 
American Gas Association, All Rights Reserved 

NFPA 54-2006 

ANSI Z223. 1-2006 

National Fuel Gas Code 

2006 Edition 

This 2006 edition incorporates changes to the 2002 edition. It was adoped by the National 
Fire Protection Association (NFPA) on July 29, 2005 and was approved by the American 
National Standards Institute, Inc. (ANSI) on August 17, 2005. The ANSI designation is 
Z223.1-2006. The NFPA designation is NFPA 54-2006. 

Origin and Development of NFPA 54 

This code offers general criteria for the installation and operation of gas piping and gas 
equipment on consumers' premises. It is the cumulative result of years of experience of many 
individuals and many organizations acquainted with the installation of gas piping and equip- 
ment designed for utilization of gaseous fuels. It is intended to promote public safety by 
providing requirements for the safe and satisfactory utilization of gas. 

Changes in this code can become necessary from time to time. When any revision is 
deemed advisable, recommendations should be forwarded to the Secretary, Accredited Stan- 
dards Committee Z223, 400 N. Capitol St. NW, Washington, DC 20001, and the Secretary, 
Standards Council, National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 
02169-7471. 

In October 1967, representatives of the American Gas Association, the American Society of 
Mechanical Engineers, and the National Fire Protection Association met as a Conference 
Group on Piping and Installation Standards to consider the development of a single National 
Fuel Gas Code. This conference was the result of the expressed need within the gas industry, 
among public safety authorities, insurance groups, architects, designers, and builders, for one 
code that would cover all facets of fuel gas piping and appliance installation downstream from 
meter set assemblies or other components comprising the gas service entrance to the con- 
sumer premises. 

At ajanuary 1968 meeting, the conference group developed the objectives and scope of a 
proposed National Standards Committee. The group envisioned the combining of the follow- 
ing standards into a single National Fuel Gas Code: 

(1) American National Standard Installation of Gas Appliances and Gas Piping, ANSI Z21.30 
(NFPA 54) 

(2) Installation of Gas Piping and Gas Equipment on Industrial Premises and Certain Other Premises, 
ANSI Z83.1 (NFPA 54A) 

(3) Fuel Gas Piping, ASME B31 .2 

The proposed scope at that time limited coverage of piping systems to 60 psi (414 kPa). 
The National Standards Committee agreed to relinquish Z21.30 (NFPA 54), Z83.1 
(NFPA 54A), and applicable portions of ASME B31.2 covering piping systems up to and 
including 60 psi (414 kPa) to a new National Fuel Gas Code Committee, co-sponsored by the 
three associations. 

On August 13, 1971, the American National Standards Institute approved the scope of activi- 
ties and the formation of the National Standards Committee on National Fuel Gas Code, Z223. 

To establish a National Fuel Gas Code to satisfy the immediate needs of the gas industry, at its 
December 6, 1972, organizational meeting the Z223 Committee combined NFPA 54-1969, 
Z21. 30-1969, and Z83. 1-1972 with only those editorial revisions necessary to reflect the scope 
of the new code. Further revisions of the code would be necessary to incorporate pertinent 
coverage for fuel gas piping from ASME B31. 2-1968. 

The first edition of the code was issued in 1974. The American Gas Association and the 
National Fire Protection Association have continued co-sponsorship of the code following the 
first edition. 



54-2 NATIONAL FUEL GAS CODE ANSI Z223. 1-2 

The second edition of the code, incorporating pertinent portions of B31.2, was issued in 1980. The third, fourth, 
fifth, sixth, and seventh editions were issued in 1984, 1988, 1992, 1996, and 1999, respectively. The scope of the code 
was expanded in 1988 to include piping systems up to and including 125 psi (862 kPa). 

The 2002 edition revised the requirements to determine whether the indoor air volume was sufficient for combus- 
tion and ventilation air needs of appliances installed within the space. A new method was added to allow the use of 
actual or calculated building air exchange rate in determining whether the indoor air volume was adequate based on 
the combustion air needs for fan-assisted combustion appliances and other appliance types. 

Codifying the longest length method and adding a new branch length method resulted in revision of the require- 
ments for gas pipe sizing. The pipe sizing tables were recalculated, and the pipe sizing equations revised. 

The 2006 edition incorporates revised steel, copper, and polyethylene pipe sizing tables with uniform lengths of 
2000 ft, except for low-pressure PE tables, which go to 500 ft. Requirements for appliance shutoff valves have been 
revised to allow manifold systems with all shutoff valves in one location up to 50 ft from the most remote appliance. The 
definitions have been reorganized by categories of definitions. Chapters containing sizing tables and appliance startup 
procedures have been relocated so that Chapters 5 through 8 cover piping, Chapters 9 through 1 1 cover installation of 
appliances, and Chapters 1 2 and 13 cover venting of appliances. In addition, consistent use of the terms appliance and 
equipment has been provided throughout the code, and the term gas utilization equipment has been discontinued. 

Prior editions of this document have been translated into languages other than English, including Spanish. 



2006 Edition 



ANSI Z223.1-3 



COMMITTEE PERSONNEL 



54-3 



Technical Committee on National Fuel Gas Code 

Mike Gorham, Chair 

Northwest LP-Gas Co., MN [IM/ES] 

Rep. National Propane Gas Association 



Paul W. Cabot, Administrative Secretary 
American Gas Association, Washington, DC (Nonvoting) 



Edward Angelone, KeySpan Energy Delivery, NY [IM/ES] 

Rep. American Gas Association 
Paul E. Beach,f Emerson Electric Company, OH [M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
C. John Beck,f Pacific Gas and Electric Company, CA [ES] 

Rep. American Gas Association 
George Bliss, f United Association, VA [IM] 
James P. Brewer, Magic Sweep Corporation, VA [IM/IM] 

Rep. National Chimney Sweep Guild 
Duane W. Brown, Ranger Insurance Company, TX [I/I] 
William H. Bruno, Bruno's Consultant Enterprises, LLC, 
MO [SE/SE] 

Thomas E. Buchal, Intertek Testing Services NA, Inc., 
NY [RT/AR-TL] 

Allen J. Callahan, CSA America, OH [RT/AR-TL] 
S. Ron Caudle,f Southern California Gas Company, 
CA [ES] 

Robert Cave,* American Public Gas Association, VA [U] 
Sharon E. Coates, State of Arkansas, AR [E/EA] 

Rep. International Fire Marshals Association 
Tim Collings,* City of Salt Lake City, UT [E] 

Rep. International Association of Plumbing 

& Mechanical Officials 
Thomas R. Crane, Crane Engineering and Forensic 
Services, MN [SE/SE] 

Mike Deegan,f American Public Gas Association, VA [ES] 
John P. Doucette, Connecticut Department of Public 
Safety, CT [E/EA] 
Glen Edgar, Selkirk, Inc., OH [M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
Alberto Jose Fossa,* MDJ Consultores Associados S/C 
Ltda, SP [SE] 

Rep. NFPA Latin American Section 
Richard L. Gilbert, Railroad Commission of Texas, 
TX [E/EA] 

Gregg A. Cress, International Code Council, IL [E/EA] 
Wilbur Haag, Jr., A. O. Smith Water Products Company, 
SC [M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 



Steen Hagensen, EXHAUSTO, Inc., GA [M/M] 
Jacob Hall,t Rheem Water Heater Division, AL [M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
J. M. Halliwill,t International Association of Plumbing 
& Mechanical Officials, CA [EA] 
Leonard Herman,! New Jersey Builder, NJ [IM] 

Rep. National Association of Home Builders 
Patricio J. Himes, Sistemas de Energia, Mexico [U/ES] 

Rep. Asociacion Mexicana Distribuidores de Gas 
Peter T. Holmes,* State of Maine, ME [E] 
Russel Iwan, Metropolitan Utilities District, NE [IM/ES] 

Rep. American Gas Association 
Michael T. Kobel,* International Association of 
Plumbing & Mechanical Officials, CA [E] 
Theodore C. Lemoff,f National Fire Protection 
Association, MA [EA] 

Brian C. Olson, National Park Service, CO [U/EA] 
Winded F. Peters, AGL Resources Inc., GA [IM/ES] 

Rep. American Gas Association 
Dale L. Powell, Copper Development Association, 
PA [M/M] 
Phttlip H. Ribbs,* Santa Cruz, CA [E] 

Rep. International Association of Plumbing 

& Mechanical Officials 
David W. Rock, City of Portland, OR [E/EA] 

Rep. Oregon Mechanical Officials Association 
Bryan Rocky, York International Corporation, KS [M] 

Rep. Gas Appliance Manufacturers Association, Inc. 
Isaac P. Sargunam, Maytag Corporation, IA [M/M] 

Rep. Association of Home Appliance Manufacturers 
John W. Wasson.f City of Greenville, SC [E/A] 
Richard E. White, Richard E. White & Associates, 
IN [U/IM] 

Rep. National Association of 

Plumbing-Heating-Cooling Contractors 
Robert Wozniak, Underwriters Laboratories Inc., 
NY [RT/AR-TL] 



2006 Edition 



54-4 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-4 



Alternates 



Paul E. Beach,* Emerson Electric Company, OH [M] 

(Alt. to W. L. Haag) 
C. John Beck,* Pacific Gas and Electric Company, CA [IM] 

(Alt. to W. F. Peters) 
C. Royal Edwards,* National Chimney Sweep Guild, 
FL [IM] 

(Alt. to J. P. Brewer) 
Jacob Hall,* Rheem Water Heater Division, AL[M/M] 

Rep. Gas Appliance Manufacturers Association, Inc. 

(Alt. to B. Rocky) 
John M. Halliwill,* International Association of Plumbing 
& Mechanical Officials, CA [E] 

(Alt. to M. T. Kobel) 
Michael T. Kobel, P.E.,f International Association of 
Plumbing & Mechanical Officials, CA [E] 

(Alt. to J. M. Halliwill) 
Gregory S. Roll, Metropolitan Utilities District, 
NE [IM/ES] 

(Alt. to R. Iwan) 



Scott Lybarger,* Ranger Insurance Company, AL [I/I] 

(Alt. to D. W. Brown) 
Martin P. Petchul, Piedmont Natural Gas Company, 
NC [IM/ES] 

(Alt. to E. Angelone) 
Stephen L. Pitner,* Railroad Commission of Texas, TX [E] 

(Alt. to R. L. Gilbert) 
Hari Ramanathan,* International Association of 
Plumbing & Mechanical Officials, CA [E] 

(Alt. to P. H. Ribbs) 
Robert E. Stack, CSAAmerica, Inc., OH [RT/AR-TL] 

(Alt. to A. J. Callahan) 
Bruce J. Swiecicki, National Propane Gas Association, 
IL [IM/ES] 

(Alt. to M. Gorham) 



Theodore C. Lemoff*, NFPA Staff Liaison 

*NFPA 54 Committee only. fZ223 Committee only. 

This list represents the membership at the time the Committee was balloted on the final text of this edition. Since that time, 
changes in the membership may have occurred. A key to classifications is found at the back of the document. 

NOTE: Membership on a committee shall not in and of itself constitute an endorsement of the Association or 
any document developed by the committee on which the member serves. 

Committee Scope: This Committee shall have primary responsibility for documents on safety code for gas 
piping systems on consumers' premises and the installation of gas utilization equipment and accessories for 
use with fuel gases such as natural gas, manufactured gas, liquefied petroleum gas in the vapor phase, 
liquefied petroleum gas-air mixtures, or mixtures of these gases, including the following: (a) The design, 
fabrication, installation, testing, operation, and maintenance of gas piping systems from the point of delivery 
to the connections with each gas utilization device. Piping systems covered by this code are limited to a 
maximum operating pressure of 125 psig. For purposes of this code, the point of delivery is defined as the 
outlet of the meter set assembly, or the outlet of the service regulator or service shutoff valve where no meter 
is provided, (b) The installation of gas utilization equipment, related accessories, and their ventilation and 
venting systems. 



2006 Edition 



ANSI Z223. 1-5 



CONTENTS 



54-5 



Contents 



Chapter 1 Administration 54— 7 

1.1 Scope 54- 7 

1.2 Purpose 54- 7 

1.3 Retroactivity 54- 7 

1.4 Equivalency 54- 8 

1.5 Enforcement 54— 8 

Chapter 2 Referenced Publications 54— 8 

2.1 General 54- 8 

2.2 NFPA Publications 54- 8 

2.3 Other Publications 54- 8 

2.4 References for Extracts in Mandatory 



Sections 



54- 9 



Chapter3 Definitions 54- 9 

3.1 General 54- 9 

3.2 NFPA Official Definitions 54- 9 

3.3 General Definitions 54— 9 

Chapter4 General 54- 16 

4.1 Qualified Agency 54- 16 

4.2 Interruption of Service 54—16 

4.3 Prevention of Accidental Ignition 54— 16 

Chapter 5 Gas Piping System Design, Materials, 

and Components 54— 17 

5.1 PipingPlan 54- 17 

5.2 Provision for Location of Point of 

Delivery 54- 17 

5.3 Interconnections Between Gas Piping 

Systems 54— 17 

5.4 Sizing of Gas Piping Systems 54— 17 

5.5 Piping System Operating Pressure 
Limitations 54— 18 

5.6 Acceptable Piping Materials and 

Joining Methods 54— 18 

5.7 GasMeters 54-20 

5.8 Gas Pressure Regulators 54— 20 

5.9 Overpressure Protection Devices 54— 21 

5.10 Back Pressure Protection 54— 22 

5.11 Low-Pressure Protection 54— 22 

5.12 ShutoffValves 54- 22 

5.13 Expansion and Flexibility 54— 22 

Chapter 6 Pipe Sizing 54- 22 

6.1 Pipe Sizing Methods 54- 22 

6.2 Tables for Sizing Gas Piping Systems 

Using Natural Gas 54- 22 

6.3 Tables for Sizing Gas Piping Systems 

Using Propane 54- 22 

6.4 Sizing Equations 54- 56 



Chapter 7 Gas Piping Installation 54— 56 

7.1 Piping Underground 54— 56 

7.2 Installation of Piping 54- 57 

7.3 Concealed Piping in Buildings 54- 58 

7.4 Piping in Vertical Chases 54- 58 

7.5 GasPipe Turns 54- 58 

7.6 Drips and Sediment Traps 54— 58 

7.7 Outlets 54- 59 

7.8 Branch Pipe Connection 54— 59 

7.9 Manual Gas ShutoffValves 54- 59 

7.10 Prohibited Devices 54-59 

7.11 Systems Containing Gas-Air Mixtures 

Outside the Flammable Range 54— 59 

7.12 Systems Containing Flammable 

Gas-Air Mixtures 54- 59 

7.13 Electrical Bonding and Grounding 54- 60 

7.14 Electrical Circuits 54- 60 

7.15 Electrical Connections 54— 60 

Chapter 8 Inspection, Testing, and Purging 54— 60 

8.1 Pressure Testing and Inspection 54— 60 

8.2 Piping System, Appliance, and 

Equipment Leakage Check 54— 61 

8.3 Purging 54- 61 

Chapter 9 Appliance, Equipment, and 

Accessory Installation 54- 62 

9.1 General 54- 62 

9.2 Accessibility and Clearance 54— 64 

9.3 Air for Combustion and Ventilation 54- 64 

9.4 Appliances on Roofs 54- 66 

9.5 Appliances in Attics 54- 66 

9.6 Appliance and Equipment 

Connections to Building Piping 54— 67 

9.7 Electrical 54- 68 

9.8 Room Temperature Thermostats 54— 68 

Chapter 10 Installation of Specific Appliances 54— 68 

10.1 General 54-68 

10.2 Air-Conditioning Appliances 
(Gas-Fired Air Conditioners and 
HeatPumps) 54- 68 

10.3 Central Heating Boilers and Furnaces .... 54— 69 

10.4 Clothes Dryers 54- 72 

10.5 Conversion Burners 54— 73 

10.6 Decorative Appliances for Installation 

in Vented Fireplaces 54— 73 

10.7 Gas Fireplaces, Vented 54- 73 

1 0.8 Non-Recirculating Direct Gas-Fired 

Industrial Air Heaters 54— 73 

10.9 Recirculating Direct Gas-Fired 

Industrial Air Heaters 54— 74 

10.10 DuctFurnaces 54- 75 

10.11 Floor Furnaces 54- 75 



2006 Edition 



54-6 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-6 



10.12 Food Service Appliance, 

Floor-Mounted 54- 76 

10.13 Food Service Appliances, Counter 

Appliances 54— 77 

10.14 Hot Plates and Laundry Stoves 54- 77 

10.15 Household Cooking Appliances 54— 77 

10.16 Illuminating Appliances 54— 78 

10.17 Incinerators, Commercial-Industrial 54— 79 

10.18 Infrared Heaters 54- 79 

10.19 Open-Top Broiler Units 54- 79 

10.20 Outdoor Cooking Appliances 54— 79 

10.21 PoolHeaters 54- 79 

10.22 Refrigerators 54- 79 

10.23 Room Heaters 54- 80 

10.24 Stationary Gas Engines 54- 80 

10.25 Gas-Fired Toilets 54- 80 

10.26 UnitHeaters 54- 80 

10.27 WallFurnaces 54- 81 

10.28 WaterHeaters 54- 81 

10.29 Compressed Natural Gas (CNG) 

Vehicular Fuel Systems 54— 82 

10.30 Appliances for Installation in 

Manufactured Housing 54— 82 

10.31 Fuel Cell Power Plants 54- 82 

Chapter 11 Procedures to Be Followed to Place 

Appliance in Operation 54— 82 

11.1 Adjusting the Burner Input 54- 82 

11.2 Primary Air Adjustment 54- 82 

11.3 Safety Shutoff Devices 54- 82 

11.4 Automatic Ignition 54- 82 

11.5 Protective Devices 54— 82 

11.6 Checking the Draft 54-82 

11.7 Operating Instructions 54- 82 

Chapter 12 Venting of Appliances 54— 82 

12.1 Minimum Safe Performance 54- 82 

12.2 General 54- 82 

12.3 Specification for Venting 54— 82 

12.4 Design and Construction 54- 83 

12.5 Type of Venting System to Be Used 54- 83 

12.6 Masonry, Metal, and Factory-Built 

Chimneys 54- 84 

12.7 Gas Vents 54- 86 

12.8 Single-Wall Metal Pipe 54- 87 

12.9 Through the Wall Vent Termination 54- 88 

12.10 Condensation Drain 54- 89 

12.11 Vent Connectors for Category I 

Appliances 54— 89 



12.12 Vent Connectors for Category II, 
Category III, and Category IV 

Appliances 54— 91 

12.13 Draft Hoods and Draft Controls 54- 91 

12.14 Manually Operated Dampers 54— 91 

12.15 Automatically Operated Vent Dampers ... 54— 91 

12.16 Obstructions 54- 91 

Chapter 13 Sizing of Category I Venting 

Systems 54- 92 

13.1 Additional Requirements to Single 

Appliance Vent 54- 92 

13.2 Additional Requirements to 
Multiple-Appliance Vent 54-100 

Annex A Explanatory Material 54—111 

Annex B Coordination of Appliance and 

Equipment Design, Construction, 

and Maintenance 54—120 

Annex C Sizing and Capacities of Gas Piping 54-121 

Annex D Suggested Method of Checking for 

Leakage 54-131 

Annex E Suggested Emergency Procedure for 

GasLeaks 54-132 

Annex F Flow of Gas Through Fixed Orifices 54-132 

Annex G Sizing of Venting Systems Serving 
Appliances Equipped with Draft 
Hoods, Category I Appliances, and 
Appliances Listed for Use with 
TypeBVents 54-137 

Annex H Recommended Procedure for Safety 
Inspection of an Existing 
Appliance Installation 54—144 

Annex I Indoor Combustion Air Calculation 

Examples 54-145 

Annex J Example of Combination of Indoor 
and Outdoor Combustion and 
Ventilation Opening Design 54—147 

AnnexK Other Useful Definitions 54-147 

Annex L Informational References 54—149 

Index 54-152 



2006 Edition 



ANSI Z223.1-7 



ADMINISTRATION 



54-7 



NFPA54 

ANSI Z223. 1-2006 

National Fuel Gas Code 

2006 Edition 

IMPORTANT NOTE: This NFPA document « made available for 
use subject to important notices and legal disclaimers. These notices 
and disclaimers appear in all publications containing this document 
and may be found under the heading "Important Notices and Dis- 
claimers Concerning NFPA Documents. " They can also be obtained 
on request from NFPA or viewed at wuiw.njpa.org/disclaimers. 

NOTICE: An asterisk (*) following the number or letter 
designating a paragraph indicates that explanatory material 
on the paragraph can be found in Annex A. 

Changes other than editorial are indicated by a vertical 
rule beside the paragraph, table, or figure in which the 
change occurred. These rules are included as an aid to the 
user in identifying changes from the previous edition. Where 
one or more complete paragraphs have been deleted, the de- 
letion is indicated by a bullet (•) between the paragraphs that 
remain. 

A reference in brackets [ ] following a section or paragraph 
indicates material that has been extracted from another NFPA 
document. As an aid to the user, the complete title and edition 
of the source documents for extracts in mandatory sections of 
the document are given in Chapter 2 and those for extracts in 
informational sections are given in Annex L. Editorial changes 
to extracted material consist of revising references to an ap- 
propriate division in this document or the inclusion of the 
document number with the division number when the refer- 
ence is to the original document. Requests for interpretations 
or revisions of extracted text shall be sent to the technical 
committee responsible for the source document. 

Information on referenced publications can be found in 
Chapter 2 and Annex L. 

All pressures used in this code are gauge pressure unless 
otherwise indicated. 



Chapter 1 Administration 



1.1 Scope. 



1.1.1 Applicability. 

1.1.1.1 This code is a safety code that shall apply to the instal- 
lation of fuel gas piping systems, appliances, equipment, and 
related accessories as shown in 1.1.1.1(A) through 1.1.1.1(D). 

(A) Coverage of piping systems shall extend from the point of 
delivery to the appliance connections. For other than undi- 
luted liquefied petroleum gas systems, the point of delivery 
shall be considered to be the outlet of the service meter assem- 
bly or the oudet of the service regulator or service shutoff valve 
where no meter is provided. For undiluted liquefied petro- 
leum gas systems, the point of delivery shall be considered to 
be the outlet of the final pressure regulator, exclusive of line 
gas regulators, in the system. 

(B) The maximum operating pressure shall be 125 psi 
(862 kPa). 



Exception No. 1: Piping systems for gas-air mixtures within the flam- 
mable range are limited to a maximum pressure of 10 psi (69kPa). 

Exception No. 2: LP-Gas piping systems are limited to 20 psi (140 
KPa), except as provided in 5.5.2. 

(C) Piping systems requirements shall include design, mate- 
rials, components, fabrication, assembly, installation, testing, 
inspection, operation, and maintenance. 

(D) Requirements for appliances, equipment and related ac- 
cessories shall include installation, combustion, and ventila- 
tion air and venting. 

1.1.1.2 This code shall not apply to the following items (ref- 
erence standards for some of which appear in Annex L): 

(1) Portable LP-Gas appliances and equipment of all types 
that are not connected to a fixed fuel piping system 

(2) Installation of farm appliances and equipment such as 
brooders, dehydrators, dryers, and irrigation equipment 

(3) Raw material (feedstock) applications except for piping 
to special atmosphere generators 

(4) Oxygen-fuel gas cutting and welding systems 

(5) Industrial gas applications using such gases as acetylene 
and acetylenic compounds, hydrogen, ammonia, carbon 
monoxide, oxygen, and nitrogen 

(6) Petroleum refineries, pipeline compressor or pumping 
stations, loading terminals, compounding plants, refin- 
ery tank farms, and natural gas processing plants 

(7) Large integrated chemical plants or portions of such plants 
where flammable or combustible liquids or gases are pn> 
duced by chemical reactions or used in chemical reactions 

(8) LP-Gas installations at utility gas plants 

(9) Liquefied natural gas (LNG) installations 

(10) Fuel gas piping in power and atomic energy plants 

(11) Proprietary items of equipment, apparatus, or instruments 
such as gas generating sets, compressors, and calorimeters 

(12) LP-Gas equipment for vaporization, gas mixing, and gas 
manufacturing 

( 1 3) LP-Gas piping for buildings under construction or reno- 
vations that is not to become part of the permanent 
building piping system — that is, temporary fixed piping 
for building heat 

(14) Installation of LP-Gas systems for railroad switch heating 

(15) Installation of LP-Gas and compressed natural gas sys- 
tems on vehicles 

(16) Gas piping, meters, gas pressure regulators, and other 
appurtenances used by the serving gas supplier in distri- 
bution of gas, other than undiluted LP-Gas 

(17) Building design and construction, except as specified 
herein 

(18) Fuel gas systems on recreational vehicles manufactured 
in accordance with NFPA 1192, Standard on Recreational 
Vehicles 

(19) Fuel gas systems using hydrogen as a fuel 

(20) Construction of appliances 

1.1.2 Other Standards. In applying this code, reference shall 
also be made to the manufacturers' instructions and the serv- 
ing gas supplier regulations. 

1.2 Purpose. (Reserved) 

1.3 Retroactivity. Unless otherwise stated, the provisions of 
this code shall not be applied retroactively to existing systems 
that were in compliance with the provisions of the code in 
effect at the time of installation. 



2006 Edition 



54-8 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-8 



1 .4 Equivalency. The provisions of this code are not intended to 
prevent the use of any material, method of construction, or in- 
stallation procedure not specifically prescribed by this code, pro- 
vided any such alternative is acceptable to the authority having 
jurisdiction (see 3.2.2). The authority having jurisdiction shall re- 
quire that sufficient evidence be submitted to substantiate any 
claims made regarding the safety of such alternatives. 

1.5* Enforcement. This code shall be administered and en- 
forced by the authority having jurisdiction designated by the 
governing authority. (See A. 1.5 for sample wording for enabling 
legislation.) 



Chapter 2 Referenced Publications 

2.1 General. The documents or portions thereof listed in this 
chapter are referenced within this code and shall be consid- 
ered part of the requirements of this document. 

2.2 NFPA Publications. National Fire Protection Association, 
1 Batterymarch Park, Quincy, MA 02169-7471. 

NFPA 30 A, Code for Motor Fuel Dispensing Facilities and Repair 
Garages, 2003 edition. 

NFPA 37, Standard for the Installation and Use of Stationary 
Combustion Engines and Gas Turbines, 2002 edition. 

NFPA 51, Standard for the Design and Installation of Oxygen- 
Fuel Gas Systems for Welding, Cutting, and Allied Processes, 2002 
edition. 

NFPA 52, Vehicular Fuel Systems Code, 2006 edition. 

NFPA 58, Liquefied Petroleum Gas Code, 2004 edition. 

NFPA 70, National Electrical Code®, 2005 edition. 

NFPA 82, Standard on Incinerators and Waste and Linen Han- 
dling Systems and Equipment, 2004 edition. 

NFPA88A, Standard for Parking Structures, 2002 edition. 

NFPA90A, Standard for the Installation ofAir-Conditioningand 
Ventilating Systems, 2002 edition. 

NFPA 90B, Standard for the Installation of Warm Air Heating 
and Air-Conditioning Systems, 2006 edition. 

NFPA 96, Standard for Ventilation Control and Fire Protection of 
Commercial Cooking Operations, 2004 edition. 

NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid 
Fuel-Burning Appliances, 2003 edition. 

NFPA 409, Standard on Aircraft Hangars, 2004 edition. 

NFPA 853, Standard for the Installation of Stationary Fuel Cell 
Power Systems, 2003 edition. 

NFPA 1192, Standard on Recreational Vehicles, 2005 edition. 

2.3 Other Publications. 

2.3.1 ASME Publications. American Society of Mechanical 
Engineers, Three Park Avenue, New York, NY 10016-5990, 
(800)843-2763, www.asme.org. 

ANSI/ASME Bl.20.1, Pipe Threads, General Purpose, Inch, 1983 
(Reaffirmed 2001). 

ANSI/ASME B16.1, Cast Iron Pipe Ranges and Ranged Fit- 
tings, Class 25, 125, 250, and 800, 1998. 

ANSI/ASME B16.20, Metal Gaskets for Pipe Flanges, Ringjoint 
Spiral Wound and Jacketed, 2000. 

ANSI/ASME B36.10, Welded and Seamless Wrought-Steel Pipe, 
2001. 



2.3.2 ASTM Publications. American Society for Testing and 
Materials, 100 Barr Harbor Drive, West Conshohocken, PA 
19428-2959, (610)832-9585, www.astm.org. 

ASTM A 53, Standard Specification for Pipe, Steel, Black and 
Hot-Dipped, Zinc-Coated Welded and Seamless, 2001. 

ASTM A 106, Standard Specification for Seamless Carbon Steel 
Pipe for High-Temperature Service, 1999. 

ASTM A 254, Standard Specification for Copper Brazed Steel Tub- 
ing, 2002. 

ASTM A 539, Standard Specification for Electric Resistance- 
Welded Coiled Steel Tubing for Gas and Fuel Oil Lines, 1999. 

ASTM B 88, Specification for Seamless Copper Water Tube, 1999. 

ASTM B 210, Specification for Aluminum-Alloy Drawn Seamless 
Tubes, 2000. 

ASTM B 241, Specification for Aluminum-Alloy Seamless Pipe 
and Seamless Extruded Tube, 2000. 

ASTM B 280, Specification for Seamhss Copper Tube for Air Con- 
ditioning and Refrigeration Field Service, 1999. 

ASTM D 2513, Standard Specification for Thermoplastic Gas 
Pressure Pipe, Tubing, and Fittings, 2001. 

ASTM F 1973, Standard Specification for Factory Assembled An- 
odeless Risers and Transition Fittings in Polyethylene (PE) and Polya- 
mide 11 (PAH) Fuel Gas Distribution Systems, 2002. 

2.3.3 CSA-America Publications. CSA-America, Inc., 8501 East 
Pleasant Valley Road, Cleveland, OH 44131, (216)524-4990, 
www.csa-america.org. 

ANSI Z21.8, Installation of Domestic Gas Conversion Burners, 
2000. 

ANSI Z21.24/CSA6.10, Standard for Connectors for Gas Appli- 
ances, 1997. 

ANSI Z21.41/CSA 6.9, Quick-Disconnect Devices for use with 
Gas Fuel Appliances, 2003. 

ANSI Z21.69/CSA 6.22, Connectors for Movable Gas Appli- 
ances, 2001. 

ANSI Z21.75/CSA6.27, Connectors for Outdoor Gas Appliances 
and Manufactured Homes, 2001. 

ANSI Z21.80/CSA3.7, Line Pressure Regulators, 2001. 

ANSI Z83.4/CSA 3.7, Non-Recirculating Direct Gas-Fired In- 
dustrial Air Heaters, 1999. 

ANSI Z83.18, Recirculating Direct Gas-Fired Industrial Air Heat- 
ers, 1990 (2000). 

ANSI LC 1/CSA 6.26, Fuel Gas Piping Systems Using Corru- 
gated Stainless Steel Tubing, 2001 . 

2.3.4 MSS Publications. Manufacturers Standardization So- 
ciety of the Valve and Fittings Industry, 124 Park Street, NE, 
Vienna, VA 22180-6671, (703)281-6613, wwu-.mss-hq.com 

MSS SP-6, Standard Finishes for Contact Faces of Pipe Ranges 
and Connecting-End Flanges of Valves and Fittings, 2001. 

ANSI/MSS SP-58, Pipe Hangers and Supports — Materials, 
Design and Manufacture, 1993. 

2.3.5 UL Publication. Underwriters Laboratories Inc., 333 
Pfmgsten Road, Northbrook, IL 60062-2096, www.ul.com. 

UL 65 1 , Schedule 40 and Schedule 80 Rigid PVC Conduit, 2003. 



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DEFINITIONS 



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2.3.6 U.S. Government Publication. U.S. Government Print- 
ing Office, Washington, DC 20402, www.gpo.gov. 

Title 49, Code of Federal Regulations, Part 192. 

2.3.7 Other Publication. 

Merriam-Webster's Collegiate Dictionary, 11th edition, Merriam- 
Webster, Inc., Springfield, MA 2003. 

2.4 References for Extracts in Mandatory Sections. 

NFPA 10 f, Life Safety Code 1 ', 2006 edition. 
NFPA211, Standard for Chimneys, Fireplaces, Vents, and Solid 
Fuel-Burning Appliances, 2003 edition. 

NFPA 501 , Standard on Manufactured Housing, 2005 edition. 



Chapter 3 Definitions 

3.1 General. The definitions contained in this chapter shall 
apply to the terms used in this code. Where terms are not 
defined in this chapter or within another chapter, they shall 
be defined using their ordinarily accepted meanings within 
the context in which they are used. Merriam-Webster's Collegiate 
Dictionary, 11th edition, shall be the source for the ordinarily 
accepted meaning. 

3.2 NFPA Official Definitions. 



3.2.1* Approved. 

tion. 



Acceptable to the authority having jurisdic- 



3.2.2* Authority Having Jurisdiction (AHJ). An organization, 
office, or individual responsible for enforcing the require- 
ments of a code or standard, or for approving equipment, 
materials, an installation, or a procedure. 

3.2.3 Labeled. Equipment or materials to which has been at- 
tached a label, symbol, or other identifying mark of an organiza- 
tion that is acceptable to the authority having jurisdiction and 
concerned with product evaluation, that maintains periodic in- 
spection of production of labeled equipment or materials, and 
by whose labeling the manufacturer indicates compliance with 
appropriate standards or performance in a specified manner. 

3.2.4* Listed. Equipment, materials, or services included in a 
list published by an organization that is acceptable to the au- 
thority having jurisdiction and concerned with evaluation of 
products or services, that maintains periodic inspection of 
production of listed equipment or materials or periodic evalu- 
ation of services, and whose listing states that either the equip- 
ment, material, or service meets appropriate designated stan- 
dards or has been tested and found suitable for a specified 
purpose. 

3.2.5 Shall. Indicates a mandatory requirement. 

3.3 General Definitions. 

3.3.1 Accessible. Having access to but which first requires the 
removal of a panel, door, or similar covering of the item de- 
scribed. 

3.3.1.1 Readily Accessible. Having direct access without the 
need of removing or moving any panel, door, or similar 
covering of the item described. 

3.3.2 Air. 

3.3.2.1 Circulating Air. Air for cooling, heating, or ventila- 
tion distributed to habitable spaces. 



3.3.2.2 Dilution Air. Air that enters a draft hood or draft 
regulator and mixes with the flue gases. 

3.3.2.3 Excess Air. Air that passes through the combustion 
chamber and the appliance flues in excess of that which is 
theoretically required for complete combustion. 

3.3.2.4 Primary Air. The air introduced into a burner that 
mixes with the gas before it reaches the port or ports. 

3.3.3 Air Conditioning. The treatment of air so as to control 
simultaneously its temperature, humidity, cleanness, and dis- 
tribution to meet the requirements of a conditioned space. 

3.3.4 Air Shutter. An adjustable device for varying the size of 
the primary air inlet(s). 

3.3.5 Anodeless Riser. An assembly of steel cased plastic pipe 
used to make the transition between plastic piping installed 
underground and metallic piping installed aboveground. 

3.3.6 Appliance. Any device that utilizes gas as a fuel or raw 
material to produce light, heat, power, refrigeration, or air 
conditioning. 

3.3.6.1 Automatically Controlled Appliance. Appliance 
equipped with an automatic burner ignition and safety 
shutoff device and other automatic devices. 

3.3.6.2 Decorative Appliance for Installation in a Vented Fire- 
place. A self-contained, freestanding, fuel-gas burning ap- 
pliance designed for installation only in a vented fireplace 
and whose primary function lies in the aesthetic effect of 
the flame. 

3.3.6.3 Direct Vent Appliances. Appliances that are con- 
structed and installed so that all air for combustion is derived 
directly from the outdoors and all flue gases are discharged to 
the outdoors. 

3.3.6.4 Fan-Assisted Combustion Appliance. An appliance 
equipped with an integral mechanical means to either draw 
or force products of combustion through the combustion 

chamber or heat exchanger. 

3.3.6.5 Food Service Appliance. 

3.3.6.5. 1 Baking and Roasting Gas Oven. An oven primarily 
intended for volume food preparation that may be com- 
posed of one or more sections or units of the following 
types: (1) cabinet oven, an oven having one or more cavities 
heated by a single burner or group of burners; (2) reel-type 
oven, an oven employing trays that are moved by mechanical 
means; or (3) sectional oven, an oven composed of one or 
more independendy heated cavities. 

3.3.6.5.2 Gas Counter Appliance. An appliance such as a 
gas coffee brewer and coffee urn and any appurtenant wa- 
ter heating appliance, food and dish warmer, hot plate, and 
griddle. 

3.3.6.5.3 Gas Deep Fat Fryer. An appliance, including a 
cooking vessel in which oils or fats are placed to such a 
depth that the cooking food is essentially supported by dis- 
placement of the cooking fluid or a perforated container 
immersed in the cooking fluid rather than by the bottom of 
the vessel, designed primarily for use in hotels, restaurants, 
clubs, and similar institutions. 



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3.3.6.5.4 Gas Range. A self-contained gas range providing 
for cooking, roasting, baking, or broiling, or any combina- 
tion of these functions, and not designed specifically for 
domestic use. 

3.3.6.5.5 Go* Steam Cooker. An appliance that cooks, de- 
frosts, or reconstitutes food by direct contact with steam. 

3.3.6.5.6 Gas Steam Generator. A separate appliance pri- 
marily intended to supply steam for use with food service 
appliances. 

3.3.6.5.7 Kettle. An appliance with a cooking chamber 
that is heated either by a steam jacket in which steam is 
generated by gas heat or by direct gas heat applied to the 
cooking chamber. 

3.3.6.6 Gas Counter Appliances. See 3.3.6.5.2. 

3.3.6.7 Household Cooking Appliance. An appliance for do- 
mestic food preparation, providing at least one function of 
(1) top or surface cooking, (2) oven cooking, or (3) broiling. 

3.3.6.7.1 Household Broiler Cooking Appliance. A unit that 
cooks primarily by radiated heat. 

3.3.6.7.2 Household Built-in Unit Cooking Appliance. A unit 
designed to be recessed into, placed upon, or attached to 
the construction of a building, but not for installation on 
the floor. 

3.3.6.8 Nonresidential Low-Heat Appliance. A commercial, in- 
dustrial, or institutional appliance needing a chimney capable 
of withstanding a continuous flue gas temperature not exceed- 
ing 1000°F (538°C). [211, 2003] 

3.3.6.9 Nonresidential Medium-Heat Appliance. A commer- 
cial, industrial, or institutional appliance needing a chimney 
capable of withstanding a continuous flue gas temperature 
not exceeding 1800°F (982°C). [211, 2003] 

3.3.6.10 Outdoor Cooking Appliance. A gas-fired cooking ap- 
pliance for outdoor use only that is provided with a means of 
support by the manufacturer and is connected to a fixed gas 
piping system. 

3.3.6.11 Vented Appliance. 

3.3.6.11.1* Category I Vented Appliance. An appliance that 
operates with a nonpositive vent static pressure and with a 
vent gas temperature that avoids excessive condensate pro- 
duction in the vent. 

3.3.6.11.2 Category II Vented Appliance. An appliance that 
operates with a nonpositive vent static pressure and with a 
vent gas temperature that may cause excessive condensate 
production in the vent. 

3.3.6.11.3 Category III Vented Appliance. An appliance that 
operates with a positive vent static pressure and with a vent 
gas temperature that avoids excessive condensate produc- 
tion in the vent. 

3.3.6.11.4 Category IV Vented Appliance. An appliance that 
operates with a positive vent static pressure and with a vent 
gas temperature that may cause excessive condensate pro- 
duction in the vent. 

3.3.7 Appliance Categorized Vent Diameter/Area. The mini- 
mum vent area/diameter permissible for Category I appli- 
ances to maintain a nonpositive vent static pressure when 
tested in accordance with nationally recognized standards. 



3.3.8 Automatic Firecheck. A device for stopping the progress 
of a flame front in burner mixture lines (flashback) and for 
automatically shutting off the fuel-air mixture. 

3.3.9 Backfire Preventer. See 3. 3. 89, Safety Blowout. 

3.3.10 Baffle. An object placed in an appliance to change 
the direction of or retard the flow of air, air-gas mixtures, or 
flue gases. 

3.3.11 Boiler. 

3.3.11.1 Hot Water Heating Boiler. A boiler designed to 
heat water for circulation through an external space heat- 
ing system. 

3.3.11.2 Hot Water Supply Boiler. A boiler used to heat wa- 
ter for purposes other than space heating. 

3.3.11.3 Low-Pressure Boiler. A boiler that supplies steam 
at a pressure not exceeding 15 psi (100 kPa), or hot water 
at a pressure not exceeding 160 psi (1100 kPa) at a tem- 
perature not exceeding 250°F (121°C). 

3.3.11.4 Steam Boiler. A boiler designed to convert water 
into steam which is supplied to an external system. 

3.3.12 Branch Line. Gas piping that conveys gas from a sup- 
ply line to the appliance. 

3.3.13 Breeching. See 3.3.106, Vent Connector. 

3.3.14 Broiler. A general term including broilers, sala- 
manders, barbecues, and other devices cooking primarily by 
radiated heat, excepting toasters. 

3.3.14.1 Unit Broiler. A broiler constructed as a separate 
appliance. 

3.3.15 Btu. Abbreviation for British thermal unit, which is the 
quantity of heat required to raise the temperature of 1 pound of 
water 1 degree Fahrenheit (equivalent to 1055 joules). 

3.3.16 Burner. A device for the final conveyance of gas, or a 
mixture of gas and air, to the combustion zone. 

3.3.16.1 Gas Conversion Burner. A unit consisting of a 
burner and its controls utilizing gaseous fuel for installa- 
tion in an appliance originally utilizing another fuel. 

3.3.16.2 Forced-Draft Burner. See 3.3. 1 6 .5, Power Burner. 

3.3.16.3 Injection (Bunsen) Type Burner. A burner employ- 
ing the energy of a jet of gas to inject air for combustion 
into the burner and mix it with the gas. 

3.3.16.4 Main Burner. A device or group of devices essen- 
tially forming an integral unit for the final conveyance of 
gas or a mixture of gas and air to the combustion zone and 
on which combustion takes place to accomplish the func- 
tion for which the appliance is designed. 

3.3.16.5 Power Burner : Aburner in which either gas or air, 
or both, are supplied at a pressure exceeding, for gas, the 
line pressure, and for air, atmospheric pressure; this added 
pressure being applied at the burner. A burner for which 
air for combustion is supplied by a fan ahead of the appli- 
ance is commonly designated as a forced-draft burner. 

3.3.16.5.1 Power, Fan-Assisted Burner. A burner that uses 
either induced or forced draft. 

3.3.17 Chimney. One or more passageways, vertical or nearly 
so, for conveying flue or vent gases to the outdoors. (See also 
3.3.105.2, GasVent, 3.3.105, Vent, and 3.3.98.7, Venting System.) 



2006 Edition 



ANSI Z223.1-11 



DEFINITIONS 



54-11 



3.3.17.1 Exterior Masonry Chimneys. Masonry chimneys ex- 
posed to the outdoors on one or more sides below the roof 
line. 

3.3.17.2 Factory-Built Chimney. A chimney composed of 
listed factory-built components assembled in accordance 
with the manufacturer's installation instructions to form 
the completed chimney. 

3.3.17.3 Masonry Chimney. Afield-constructed chimney of 
solid masonry units, bricks, stones, listed masonry chimney 
units, or reinforced pordand cement concrete, lined with 
suitable chimney flue liners. 

3.3.17.4 Metal Chimney. A field-constructed chimney of 
metal. 

3.3.18 Clothes Dryer. An appliance used to dry wet laundry by 
means of heat derived from the combustion of fuel gases. 

3.3.18.1 Type 1 Clothes Dryer. Primarily used in family liv- 
ing environment. May or may not be coin-operated for 
public use. 

3.3.18.2 Type 2 Clothes Dryer. Used in business with direct 
intercourse of the function with the public. May or may not 
be operated by public or hired attendant. May or may not 
be coin-operated. 

3.3.19 Combustion. As used herein, the rapid oxidation of 
fuel gases accompanied by the production of heat or heat and 
light. Complete combustion of a fuel is possible only in the 
presence of an adequate supply of oxygen. 

3.3.20 Combustion Chamber. The portion of an appliance 
within which combustion occurs. 

3.3.21 Combustion Products. Constituents resulting from the 
combustion of a fuel with the oxygen of the air, including the 
inert but excluding excess air. 

3.3.22 Condensate (Condensation). The liquid that separates 
from a gas (including flue gas) due to a reduction in tempera- 
ture or an increase in pressure. 

3.3.23 Consumption. The maximum amount of gas per unit 
of time, usually expressed in cubic feet per hour, or Btu per 
hour, required for the operation of the appliance or appli- 
ances supplied. 

3.3.24 Controls. Devices designed to regulate the gas, air, wa- 
ter, or electrical supply to an appliance. These may be manual 
or automatic. 

3.3.24.1 Limit Control. A device responsive to changes in 
pressure, temperature, or liquid level for turning on, shut- 
ting off, or throttling the gas supply to an appliance. 

3.3.25 Cubic Foot (ft 3 ) of Gas. The amount of gas that would 
occupy 1 ft 3 (0.03 m 3 ) when at a temperature of 60°F (16°C), 
saturated with water vapor and under a pressure equivalent to 
that of 30 in. w.c. (7.5 kPa) . 

3.3.26 Deep Fat Fryer. See 33.6.5.3, Gas Deep Fat Fryer. 

3.3.27 Design Certification. The process by which a product 
is evaluated and tested by an independent laboratory to affirm 
that the product design complies with specific requirements. 

3.3.28 Device. 

3.3.28.1 Automatic Gas Shutoff Device. A device constructed 
so that the attainment of a water temperature in a hot water 
supply system in excess of some predetermined limit acts in 
such a way as to cause the gas to the system to be shut off. 



3.3.28.2 Pressure Limiting Device. Equipment that under 
abnormal conditions will act to reduce, restrict, or shut off 
the supply of gas flowing into a system in order to prevent 
the gas pressure in that system from exceeding a predeter- 
mined value. 

3.3.28.3 Quick-Disconnect Device. A hand-operated device 
that provides a means for connecting and disconnecting an 
appliance or an appliance connector to a gas supply and 
that is equipped with an automatic means to shut off the 
gas supply when the device is disconnected. 

3.3.28.4 Safety Shutoff Device. A device that will shut off the 
gas supply to the controlled burner(s) in the event the 
source of ignition fails. This device can interrupt the flow 
of gas to main burner(s) only or to pilot(s) and main burn- 
er^) under its supervision. 

3.3.28.5 Vent Damper Device. 

3.3.28.5.1 Automatic Vent Damper Device. A device that is 
intended for installation in the venting system, in the outlet 
of or downstream of the appliance draft hood, of an indi- 
vidual automatically operated appliance and that is de- 
signed to automatically open the venting system when the 
appliance is in operation and to automatically close off the 
venting system when the appliance is in a standby or shut- 
down condition. 

3.3.28.5.2 Electrically Operated, Automatic Vent Damper Device. 
An automatic vent damper device that employs electrical 
energy to control the device. 

3.3.28.5.3 Mechanically Actuated, Automatic Vent Damper 
Device. An automatic vent damper device dependentfor op- 
eration on the direct application or transmission of mechani- 
cal energy without employing any type of energy conversion. 

3.3.28.5.4 Thermally Actuated, Automatic Vent Damper De- 
vice. An automatic vent damper device dependent for op- 
eration exclusively on the direct conversion of the thermal 
energy of the vent gases into mechanical energy. 

3.3.29 Diversity Factor. Ratio of the maximum probable de- 
mand to the maximum possible demand. 

3.3.30 Domestic Laundry Stove. A fuel-gas burning appliance 
consisting of one or more open-top-type burners mounted on 
high legs or having a cabinet base. 

3.3.31 Draft A pressure difference that causes gases or air to 
flow through a chimney, vent, flue, or appliance. 

3.3.31.1 Mechanical Draft. Draft produced by a fan or an 
air or steam jet. When a fan is located so as to push the flue 
gases through the chimney or vent, the draft is forced. 
When the fan is located so as to pull the flue gases through 
the chimney or vent, the draft is induced. [211, 2003] 

3.3.31.2 Natural Draft. Draft produced by the difference 
in the weight of a column of flue gases within a chimney or 
vent and a corresponding column of air of equal dimen- 
sion outside the chimney or vent. [211, 2003] 

3.3.32 Draft Hood. A nonadjustable device built into an ap- 
pliance, or made a part of the vent connector from an appli- 
ance, that is designed to (1) provide for the ready escape of 
the flue gases from the appliance in the event of no draft, 
backdraft, or stoppage beyond the draft hood, (2) prevent a 
backd raft from entering the appliance, and (3) neutralize the 



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NATIONAL FUEL GAS CODE 



ANSI Z223.1-12 



effect of stack action of the chimney or gas vent upon the 
operation of the appliance. 

3.3.33 Drip. The container placed at a low point in a system of 
piping to collect condensate and from which it may be removed. 

3.3.34 Dry Gas. A gas having a moisture and hydrocarbon 
dew point below any normal temperature to which the gas 
piping is exposed. 

3.3.35 Effective Ground-Fault Current Path. An intentionally 
constructed, permanent, low impedance electrically conduc- 
tive path designed and intended to carry electric fault current 
from the point of a ground fault on a wiring system to the 
electrical supply source. 

3.3.36 Equipment. Devices other than appliances. 

3.3.37 Explosion Heads (Soft Heads or Rupture Discs). A pro- 
tective device for relieving excessive pressure in a premix sys- 
tem by bursting of a rupturable disc. 

3.3.38 FAN Max. The maximum input rating of a Category I, 
fan-assisted appliance attached to a vent or connector. 

3.3.39 FAN Min. The minimum input rating of a Category I, 
fan-assisted appliance attached to a vent or connector. 

3.3.40 FAN+FAN. The maximum combined appliance input 
rating of two or more Category I, fan-assisted appliances at- 
tached to the common vent. 

3.3.41 FAN+NAT. The maximum combined appliance input 
raring of one or more Category I, fan-assisted appliances and 
one or more Category I, draft hood-equipped appliances at- 
tached to the common vent. 

3.3.42 Fireplace. A fire chamber and hearth constructed of 
noncombustible material for use with solid fuels and provided 
with a chimney. 

3.3.42.1 Gas Fireplace. 

3.3.42.1.1 Direct Vent Gas Fireplace. A system consisting of 
( 1 ) an appliance for indoor installation that allows the view 
of flames and provides the simulation of a solid fuel fire- 
place, (2) combustion air connections between the appli- 
ance and the vent-air intake terminal, (3) flue-gas connec- 
tions between the appliance and the vent-air intake 
terminal, (4) a vent-air intake terminal for installation out- 
doors, constructed such that all air for combustion is ob- 
tained from the outdoor atmosphere and all flue gases are 
discharged to the outdoor atmosphere. 

3.3.42.1.2 Vented Gas Fireplace. A vented appliance that 
allows the view of flames and provides the simulation of a 
solid fuel fireplace. 

3.3.43 Flame Arrester. A nonvalve device for use in a gas-air 
mixture line containing a means for temporarily stopping the 
progress of a flame front (flashback). 

3.3.44 Flue. 

3.3.44.1 Appliance Flue. The passage(s) within an appli- 
ance through which combustion products pass from the 
combustion chamber of the appliance to the draft hood 
inlet opening on an appliance equipped with a draft hood 
or to the outlet of the appliance on an appliance not 
equipped with a draft hood. 

3.3.44.2 Chimney Flue. The passage (s) in a chimney for 
conveying the flue or vent gases to the outdoors. 



3.3.45 Flue Collar. That portion of an appliance designed for 
the attachment of a draft hood, vent connector, or venting 
system. 

3.3.46 Furnace. 

3.3.46.1 Central Furnace. A self-contained appliance for 
heating air by transfer of heat of combustion through 
metal to the air and designed to supply heated air through 
ducts to spaces remote from or adjacent to the appliance 
location. 

3.3.46.2 Direct Vent Wall Furnace. A system consisting of an 
appliance, combustion air, and flue gas connections be- 
tween the appliance and the outdoor atmosphere, and a 
vent cap supplied by the manufacturer and constructed so 
that all air for combustion is obtained from the outdoor 
atmosphere and all flue gases are discharged to the out- 
door atmosphere. 

3.3.46.3 Duct Furnace. A furnace normally installed in dis- 
tribution ducts of air conditioning systems to supply warm 
air for hearing. This definition applies only to an appliance 
that depends for air circulation on a blower not furnished 
as part of the furnace. 

3.3.46.4 Enclosed Furnace. A specific heating, or heating 
and ventilating, furnace incorporating an integral total en- 
closure and using only outdoor air for combustion. 

3.3.46.5 Floor Furnace. A completely self-contained unit 
furnace suspended from the floor of the space being 
heated, taking air for combustion from outside this space. 

3.3.46.6 Forced-Air Furnace. A furnace equipped with a fan 
or blower that provides the primary means for circulation 
of air. 

3.3.46.7 Vented Wall Furnace. A self-contained, vented, 
fuel-gas-burning appliance complete with grilles or equiva- 
lent, designed for incorporation in or permanent attach- 
ment to the structure of a building and furnishing heated 
air, circulated by gravity or by a fan, directly into the space 
to be heated through openings in the casing. 

3.3.47 Furnace Plenum. A compartment or chamber that is 
supplied with the furnace or constructed of ductwork that is 
attached to the inlet or oudet of a furnace or air handling unit 
and has one or more circulating air ducts connected to it. 

3.3.48 Garage. 

3.3.48.1 Repair Garage. A building, structure, or portions 
thereof wherein major repair or painting or body and 
fender work is performed on motorized vehicles or auto- 
mobiles, and includes associated floor space used for of- 
fices, parking, and showrooms. 

3.3.48.2 Residential Garage. A building or room in which 
self-propelled passenger vehicles are or can be stored and 
that will not normally be used for other than minor service 
or repair operations on such stored vehicles. 

3.3.49 Gas Convenience Oudet. A permanently mounted, 
hand-operated device providing a means for connecting and 
disconnecting an appliance or an appliance connector to the 
gas supply piping. The device includes an integral, manually 
operated gas valve with a nondisplaceable valve member so 
that disconnection can be accomplished only when the manu- 
ally operated gas valve is in the closed position. 



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DEFINITIONS 



54-13 



3.3.50 Gases. Include natural gas, manufactured gas, lique- 
fied petroleum (LP) gas in the vapor phase only, liquefied 
petroleum gas-air mixtures, and mixtures of these gases, plus 
gas-air mixtures within the flammable range, with the fuel gas 
or the flammable component of a mixture being a commer- 
cially distributed product. 

3.3.50.1 Flue Gases. Products of combustion plus excess 
air in appliance flues or heat exchangers. 

3.3.50.2 Utility Gases. Natural gas, manufactured gas, liq- 
uefied petroleum gas-air mixtures, or mixtures of any of 
these gases. 

3.3.50.3 Vent Gases. Products of combustion from appli- 
ances plus excess air, plus dilution air in the venting system 
above the draft hood or draft regulator. 

3.3.51 Gas-Fired Air Conditioner. An automatically operated 
appliance for supplying cooled and/or dehumidified air or 
chilled liquid. 

3.3.52 Gas-Fired Heat Pump. An automatically operated ap- 
pliance utilizing a refrigeration system for supplying either 
heated air or liquid or heated and/or cooled air or liquid. 

3.3.53 Gas-Mixing Machine. Any combination of automatic 
proportioning control devices, blowers, or compressors that 
supply mixtures of gas and air to multiple burner installations 
where control devices or other accessories are installed be- 
tween the mixing device and burner. 

3.3.54 Gravity. See 3.3. 94, Specific Gravity. 

3.3.55 Heater. 

3.3.55.1 Direct Gas-Fired N(mrecirculating Industrial Air 
Heater. A nonrecirculating industrial air heater in which 
all the products of combustion generated by the appliance 
are released into the outdoor airstream being heated. 

3.3.55.2 Direct Gas-Fired Recirculating Industrial Air Heater. 

An air recirculating heater in which all of the products of 
combustion generated by the appliance are released into 
the airstream being heated. 

3.3.55.3 Infrared Heater. A heater that directs a substantial 
amount of its energy output in the form of infrared energy 
into the area to be heated. Such heaters may be of either 
the vented or unvented type. 

3.3.55.4 Pool Heater. An appliance designed for heating 
nonpotable water stored at atmospheric pressure, such as 
water in swimming pools, therapeutic pools, and similar 
applications. 

3.3.55.5 Unit Heater. 

3.3.55.5.1 High-Static Pressure Type Unit Heater. A self- 
contained, automatically controlled, vented, appliance 
having integral means for circulation of air against 0.2 in. 
(15 mm) H 2 or greater static pressure. 

3.3.55.5.2 Low-Static Pressure Type Unit Heater. A self- 
contained, automatically controlled, vented, fuel-gas burning 
appliance, intended for installation in the space to be heated 
without the use of ducts, having integral means for circulation 
of air, normally by a propeller fan(s), and may be equipped 
with louvers or face extensions made in accordance with the 
manufacturers' specifications. 



3.3.55.6 Unvented Room Heater. An unvented, self- 
contained, freestanding, nonrecessed, fuel-gas-burning ap- 
pliance for furnishing warm air by gravity or fan circulation 
to the space in which installed, directly from the heater 
without duct connection. 

3.3.55.7 Water Heater. An appliance for supplying hot wa- 
ter for domestic or commercial purposes. 

3.3.56 Heating Value (Total). The number of British thermal 
units produced by the combustion, at constant pressure, of 
1 ft 3 (0.03 m 3 ) of gas when the products of combustion are 
cooled to the initial temperature of the gas and air, when the 
water vapor formed during combustion is condensed, and 
when all the necessary corrections have been applied. 

3.3.57 Hot Plate. See 3.3.6.5.2, Gas Counter Appliance. 

3.3.57.1 Domestic Hot Plate. A fuel-gas burning appliance 
consisting of one or more open-top-type burners mounted 
on short legs or a base. 

3.3.58 Hot Taps. Piping connections made to operating 
pipelines or mains or other facilities while they are in opera- 
tion. The connection of the branch piping to the operating 
line and the tapping of the operating line are done while it is 
under gas pressure. 

3.3.59 Ignition. 

3.3.59.1 Automatic Ignition, Ignition of gas at the burn- 
er(s) when the gas controlling device is turned on, includ- 
ing reignition if the flames on the burner(s) have been 
extinguished by means other than by the closing of the gas 
controlling device. 

3.3.59.2 Sources of Ignition. Appliances or equipment that, 
because of their intended modes of use or operation, are 
capable of providing sufficient thermal energy to ignite 
flammable gas-air mixtures. 

3.3.60 Insulating Millboard. Afactory fabricated board formed 
with noncombustible materials, normally fibers, and having a 
thermal conductivity in the range of 1 Btu/in./ft 2 /°F/hr 
(0.14W/m/°K). 

3.3.61 Kettle. See 3.3.6.5.7. 

3.3.62 Leak Check. An operation performed on a complete 
gas piping system, the connections and appliances, and equip- 
ment to verify that the system does not leak. 

3.3.63 Manifold. 

3.3.63.1 Common Vent Manifold. A horizontal extension of 
the common vent within the room in which the appliances 
are installed. 

3.3.63.2 Gas Manifold. The conduit of an appliance that 
supplies gas to the individual burners. 

3.3.64 Manufactured Home. A structure, transportable in one 
or more sections, which, in the traveling mode, is 8 body-ft 
(2.4 m) or more in width or 40 body-ft (12.2 m) or more in 
length or, when erected on site, is 320 ft 2 (29.7 m 2 ) or more and 
which is built on a permanent chassis and designed to be used as 
a dwelling, with or without a permanent foundation, when con- 
nected to the required utilities, and includes plumbing, heating, 
air-conditioning, and electrical systems contained therein; ex- 
cept that such terms shall include any structure which meets all 
the requirements of this paragraph except the size requirements 
and with respect to which the manufacturer voluntarily files a 



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NATIONAL FUEL GAS CODE 



ANSI Z223.1-14 



certification required by the regulatory agency. Calculations used 
to determine the number of square feet in a structure are based 
on the structure's exterior dimensions, measured at the largest 
horizontal projections when erected on site. These dimensions 
include all expandable rooms, cabinets, and other projections 
containing interior space, but do not include bay windows. 
[501, 2005] 

3.3.65 Material. 

3.3.65.1 Combustible Material. As pertaining to materials 
adjacent to or in contact with heat-producing appliances, vent 
connectors, gas vents, chimneys, steam and hot water pipes, 
and warm air ducts, shall mean materials made of or surfaced 
with wood, compressed paper, plant fibers, or other materials 
that are capable of being ignited and burned. Such material 
shall be considered combustible even though flame-proofed, 
fire-retardant treated, or plastered. 

3.3.65.2 Noncombustible Material. For the purpose of this 
code, noncombustible material shall mean material that is 
not capable of being ignited and burned, such as material 
consisting entirely of, or of a combination of, steel, iron, 
brick, tile, concrete, slate, asbestos, glass, and plaster. 

3.3.66 Meter. An instrument installed to measure the volume 
of gas delivered through it. 

3.3.67 Mixing Blower. A motor-driven blower to produce gas- 
air mixtures for combustion through one or more gas burners 
or nozzles on a single-zone industrial heating appliance or on 
each control zone of a multizone industrial appliance or on 
each control zone of a multizone installation. 

3.3.68 NA. Vent configuration is not allowed due to potential 
for condensate formation or pressurization of the venting sys- 
tem, or not applicable due to physical or geometric restraints. 

3.3.69 NAT Max. The maximum input rating of a Category I, 
draft hood-equipped appliance attached to a vent or connector. 

3.3.70 NAT+NAT. The maximum combined appliance input 
rating of two or more Category I, draft hood-equipped appli- 
ances attached to the common vent. 

3.3.71 Occupancy. 

3.3.71.1 Health Care Occupancy. An occupancy used for 
purposes of medical or other treatment or care of four or 
more persons where such occupants are mostly incapable 
of self-preservation due to age, physical or mental disability, 
or because of security measures not under the occupants' 
control. [101, 2006] 

3.3.71.2 Residential Board and Care Occupancy. A building 
or portion thereof that is used for lodging and boarding of 
four or more residents, not related by blood or marriage to 
the owners or operators, for the purpose of providing per- 
sonal care services. [101, 2006] 

3.3.72 Orifice. The opening in a cap, spud, or other device 
whereby the flow of gas is limited and through which the gas is 
discharged to the burner. 

3.3.73 Oven, Gas Baking and Roasting. See 3. 3. 6. 5. 1, Baking 
and Roasting Gas Oven. 

3.3.74 Parking Structure. A building, structure, or portion 
thereof used for the parking of motor vehicles. 

3.3.74.1 Basement or Underground Parking Structure. A 

parking structure or portion thereof located below grade. 



3.3.74.2 Enclosed Parking Structure. Having exterior en- 
closing walls that have less than 25 percent of the total wall 
area open to atmosphere at each level using at least two 
sides of the structure. 

3.3.75 Pilot. A small flame that is utilized to ignite the gas at 
the main burner or burners. 

3.3.76 Pipe. Rigid conduit of iron, steel, copper, brass, alu- 
minum, or plastic. 

3.3.76.1 Equivalent Length Pipe. The resistance of valves, 
controls, and fittings to gas flow expressed as equivalent 
length of straight pipe for convenience in calculating pipe 
sizes. 

3.3.77 Piping. As used in this code, either pipe, tubing, or 
both. See 3.3. 76, Pipe; 3.3.102, Tubing. 

3.3.77.1 Concealed Gas Piping. Gas piping that, when in 
place in a finished building, would require removal of per- 
manent construction to gain access to the piping. 

3.3.77.2 Control Piping. All piping, valves, and fittings 
used to interconnect air, gas, or hydraulically operated con- 
trol apparatus or instrument transmitters and receivers. 

3.3.78 Plenum. A compartment or chamber to which one or 
more ducts are connected and that forms part of the air distri- 
bution system. 

3.3.79 Pressure. Unless otherwise stated, is expressed in 
pounds per square inch above atmospheric pressure. 

3.3.79.1 Atmospheric Pressure. The pressure of the weight of 
air on the surface of the earth, approximately 14.7 pounds per 
square inch (psia) (101 kPa absolute) at sea level. 

3.3.79.2 Back Pressure. Pressure against which a fluid is 
flowing, resulting from friction in lines, restrictions in 
pipes or valves, pressure in vessel to which fluid is flowing, 
hydrostatic head, or other impediment that causes resis- 
tance to fluid flow. 

3.3.79.3 Design Pressure. The maximum operating pres- 
sure permitted by this code, as determined by the design 
procedures applicable to the materials involved. 

3.3.79.4 Maximum Working Pressure. The maximum pres- 
sure at which a piping system may be operated in accor- 
dance with the provisions of this code. 

3.3.80 Pressure Drop. The loss in pressure due to friction or 
obstruction in pipes, valves, fittings, regulators, and burners. 

3.3.81 Pressure Test. An operation performed to verify the 
gastight integrity of gas piping following its installation or 
modification. 

3.3.82 Purge. To free a gas conduit of air or gas, or a mixture 
of gas and air. 

3.3.83 Qualified Agency. Any individual, firm, corporation, or 
company that either in person or through a representative is en- 
gaged in and is responsible for (a) the installation, testing, or 
replacement of gas piping or (b) the connection, installation, 
testing, repair, or servicing of appliances and equipment; that is 
experienced in such work; that is familiar with all precautions 
required; and that has complied with all the requirements of the 
authority havingjurisdiction. 

3.3.84 Range. See 3. 3. 6. 5. 4, Gas Range . 



2006 Edition 



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DEFINITIONS 



54-15 



3.3.85 Refrigerator (Using Gas Fuel). An appliance that is de- 
signed to extract heat from a suitable chamber. 

3.3.86 Regulator. 

3.3.86.1 Appliance Regulator. A pressure regulator for con- 
trolling pressure to the appliance manifold. 

3.3.86.2 Draft Regulator. A device that functions to main- 
tain a desired draft in the appliance by automatically reduc- 
ing the draft to the desired value. 

3.3.86.2.1 Barometric Draft Regulator. A balanced damper 
device attached to a chimney, vent connector, breeching, 
or flue gas manifold to control chimney draft. 

3.3.86.3 Line Gas Regulator. A pressure regulator placed 
in a gas line between the service regulator and the appli- 
ance regulator. 

3.3.86.4 Monitoring Regulator. A pressure regulator set in 
series with another pressure regulator for the purpose of 
automatically taking over in an emergency the control of 
the pressure downstream of the regulator in case that pres- 
sure tends to exceed a set maximum. 

3.3.86.5 Pressure Regulator. Equipment placed in a gas 
line for reducing, controlling, and maintaining the pres- 
sure in that portion of the piping system downstream of the 
equipment. 

3.3.86.6 Series Regulator. A pressure regulator in series 
with one or more other pressure regulators. 

3.3.86.7 Service Regulator. A pressure regulator installed 
by the serving gas supplier to reduce and limit the service 
line gas pressure to delivery pressure. 

3.3.87 Relief Opening. The opening provided in a draft hood 
to permit the ready escape to the atmosphere of the flue prod- 
ucts from the draft hood in the event of no draft, backdraft, or 
stoppage beyond the draft hood and to permit inspiration of air 
into the draft hood in the event of a strong chimney updraft. 

3.3.88 Room Large in Comparison with Size of Appliance. 

Rooms having a volume equal to at least 12 times the total 
volume of a furnace or air-conditioning appliance and at least 
16 times the total volume of a boiler. 

3.3.89 Safety Blowout (Backfire Preventer). A protective de- 
vice located in the discharge piping of large mixing machines, 
incorporating a bursting disc for excessive pressure release, 
means for stopping a flame front, and an electric switch or 
other release mechanism for actuating a built-in or separate 
safety shutoff. 

3.3.90 Service Head Adapter. A transition fitting for use with 
plastic piping (which is encased in non-pressure-carrying 
metal pipe) that connects the metal pipe casing and plastic 
pipe and tubing to the remainder of the piping system. 

3.3.91 Service Meter Assembly. The piping and fittings in- 
stalled by the serving gas supplier to connect the inlet side of 
the meter to the gas service and to connect the outlet side of 
the meter to the customer's house or yard piping. 

3.3.92 Service Regulator. See 3.3.86.5, Pressure Regulator; 
and 3.3.86.7, Service Regulator. 

3.3.93 Shutoff. See 3.3. 103, Valve. 

3.3.94 Specific Gravity. As applied to gas, the ratio of the 
weight of a given volume to that of the same volume of air, 
both measured under the same conditions. 



3.3.95 Steam Cooker. See 3.3.6.5.5, Gas Steam Cooker. 

3.3.96 Steam Generator. See 3.3.6.5.6, Gas Steam Generator. 

3.3.97 Stress. The resultant internal force that resists change 
in the size or shape of a body acted on by external forces. In 
this code, stress is often used as being synonymous with unit 
stress, which is the stress per unit area (psi) . 

3.3.97.1 Hoop Stress. The stress in a pipe wall, acting cir- 
cumferentially in a plane perpendicular to the longitudinal 
axis of the pipe and produced by the pressure of the fluid 
in the pipe. 

3.3.98 System. 

3.3.98.1 Central Premix System. A system that distributes 
flammable gas-air mixtures to two or more remote stations. 

3.3.98.2 Fan-Assisted Combustion System. An appliance 
equipped with an integral mechanical means to either 
draw or force products of combustion through the combus- 
tion chamber or heat exchanger. 

3.3.98.3 Hybrid Pressure System. A piping system in which 
the pressure at the point of delivery is reduced by one or more 
line pressure regulators prior to the appliance connection. 

3.3.98.4 Mechanical Exhaust System. Equipment installed 
in and made a part of the vent, to provide the required flow 
of gases through the vent. 

3.3.98.5 Natural Draft Venting System. A venting system that 
relies on natural draft to convey the products of combustion. 

3.3.98.6 Piping System. All piping, valves, and fittings from 
the oudet of the point of delivery from the supplier to the 
oudets of the equipment shutoff valves. 

3.3.98.7* Venting System. A continuous open passageway 
from the flue collar or draft hood of an appliance to the 
outdoors for the purpose of removing flue or vent gases. 

3.3.98.7.1 Forced Mechanical Draft Venting System. A vent- 
ing system in which a fan or other mechanical device is 
used to cause the flow of flue or vent gases under positive 
vent pressure. 

3.3.98.7.2 Mechanical Draft Venting System. A venting sys- 
tem designed to remove flue or vent gases by mechanical 
means, which may consist of an induced draft portion un- 
der nonpositive static pressure or a forced draft portion 
under positive static pressure. 

3.3.99 Tensile Strength. The highest unit tensile stress (re- 
ferred to the original cross section) a material can sustain be- 
fore failure (psi) . 

3.3.100 Thermostat. 

3.3.100.1 Electric Switch Type Thermostat. A device that 
senses changes in temperature and controls electrically, by 
means of separate components, the flow of gas to the burn- 
er^) to maintain selected temperatures. 

3.3.100.2 Integral Gas Valve Type Thermostat. An automatic 
device, actuated by temperature changes, designed to control 
the gas supply to the burner(s) in order to maintain tempera- 
tures between predetermined limits and in which the thermal 
actuating element is an integral part of the device: (1) gradu- 
ating thermostat, a thermostat in which the motion of the 
valve is approximately in direct proportion to the effective 
motion of the thermal element induced by temperature 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSIZ223.1-16 



change; (2) snap-acting thermostat, a thermostat in which the 
thermostatic valve travels instantly from the closed to the 
open position, and vice versa. 

3.3.101 Thread Joint Compounds. Nonhardening materials 
used on pipe threads to ensure a seal. 

3.3.102 Tubing. Semirigid conduit of copper, steel, alumi- 
num, CSST, or plastic. 

3.3.103 Valve. A device used in piping to control the gas sup- 
ply to any section of a system of piping or to an appliance. 

3.3.103.1 Appliance Shutoff Valve. A valve located in the 
piping system, used to shut off individual equipment. 

3.3.103.2 Automatic Valve. An automatic or semiautomatic 
device consisting essentially of a valve and operator that 
control the gas supply to the burner(s) during operation of 
an appliance. 

3.3.103.3 Manual Reset Valve. An automatic shutoff valve 
installed in the gas supply piping and set to shut off when 
unsafe conditions occur. The device remains closed until 
manually reopened. 

3.3.103.4 Relief Valve. A safety valve designed to forestall 
the development of a dangerous condition by relieving ei- 
ther pressure, temperature, or vacuum in a hot water sup- 
ply system. 

3.3.103.4.1 Pressure Relief Valve. A valve that automatically 
opens and closes a relief vent, depending on whether the 
pressure is above or below a predetermined value. 

3.3.103.4.2 Temperature Relief Valve. A valve that automati- 
cally opens and automatically closes a relief vent, depend- 
ing on whether the temperature is above or below a prede- 
termined value. 

3.3.103.4.3 Vacuum Relief Valve. A valve that automatically 
opens and closes a vent for relieving a vacuum within the hot 
water supply system, depending on whether the vacuum is 
above or below a predetermined value. 

3.3.103.5 Service Shutoff Valve. A valve, installed by the 
serving gas supplier between the service meter or source of 
supply and the customer piping system, to shut off the en- 
tire piping system. 

3.3.104 Valve Member. That part of a gas valve rotating within 
or in respect to the valve body that, by its position with respect 
to the valve body, controls the flow of gas. 

3.3.104.1 Nondisplaceable Valve Member. A valve member 
that cannot be moved from its seat by a force applied to the 
handle or to any exterior portion of the valve. 

3.3.105 Vent. A passageway used to convey flue gases from 
appliances or their vent connectors to the outdoors. 

3.3.105.1 Common Vent. That portion of a vent or chimney 
system that conveys products of combustion from more 
than one appliance. 

3.3.105.2 Gas Vent A passageway composed of listed factory- 
built components assembled in accordance with the manufac- 
turer's installation instructions for conveying vent gases from 
appliances or their vent connectors to the outdoors. 

3.3.105.2.1 Special Type Gas Vent. Gas vents for venting 
listed Category II, III, and IV appliances. 



3.3.105.2.2 Type B Gas Vent. A vent for venting listed gas 
appliances with draft hoods and other Category I appli- 
ances listed for use with Type B gas vents. 

3.3.105.2.3 Type B-W Gas Vent. A vent for venting listed 
wall furnaces. 

3.3.105.2.4 Type L Gas Vent. A vent for venting appliances 
listed for use with Type L vents and appliances listed for use 
with Type B gas vents. 

3.3.105.3 Regulator Vent. The opening in the atmospheric 
side of the regulator housing permitting the in and out 
movement of air to compensate for the movement of the 
regulator diaphragm. 

3.3.106 Vent Connector. The pipe or duct that connects a 
fuel-gas-burning appliance to a vent or chimney. 

3.3.107 Vent Offset. An arrangement of two or more fittings 
and pipe installed for the purpose of locating a vertical section 
of vent pipe in a different but parallel plane with respect to an 
adjacent section of vertical vent pipe. 

3.3.108 Venting. Removal of combustion products as well as 
process fumes to the outer air. 

3.3.109 Wall Head Adapter. A transition fitting for terminat- 
ing plastic pipe inside of buildings at the building wall. 

3.3.110 Zero Governor. A regulating device that is normally 
adjusted to deliver gas at atmospheric pressure within its flow 
rating. 



Chapter 4 General 

4.1 Qualified Agency. Installation, testing, and replacement 
of gas piping, appliances, or accessories, and repair and servic- 
ing of equipment, shall be performed only by a qualified 
agency. 

4.2 Interruption of Service. 

4.2.1 Notification of Interrupted Service. When the gas sup- 
ply is to be turned off, it shall be the duty of the qualified 
agency to notify all affected users. Where two or more users 
are served from the same supply system, precautions shall be 
exercised to ensure that service only to the proper user is 
turned off. 

Exception: In cases of emergency, affected users shall be notified as 
soon as possible of the actions taken by the qualified agency. 

4.2.2 Work Interruptions. When interruptions in work occur 
while repairs or alterations are being made to an existing pip- 
ing system, the system shall be left in a safe condition. 

4.3 Prevention of Accidental Ignition. 

4.3.1 Potential Ignition Sources. Where work is being per- 
formed on piping that contains or has contained gas, the fol- 
lowing shall apply: 

(1) Provisions for electrical continuity shall be made before 
alterations are made in a metallic piping system. 

(2) Smoking, open flames, lanterns, welding, or other sources of 
ignition shall not be permitted. 



2006 Edition 



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GAS PIPING SYSTEM DESIGN, MATERIALS, AND COMPONENTS 



54-17 



(3) A metallic electrical bond shall be installed around the loca- 
tion of cuts in metallic gas pipes made by other than cutting 
torches. Where cutting torches, welding, or other sources of 
ignition are unavoidable, it shall be determined that all 
sources of gas or gas-air mixtures have been secured and 
that all flammable gas or liquids have been cleared from the 
area. Piping shall be purged as required in Section 8.3 be- 
fore welding or cutting with a torch is attempted. 

(4) Artificial illumination shall be restricted to listed safety- 
type flashlights and safety lamps. Electric switches shall 
not be operated, on or off. 

4.3.2 Handling of Flammable Liquids. 

4.3.2.1 Drip Liquids. Liquid that is removed from a drip in 
existing gas piping shall be handled to avoid spillage or igni- 
tion. The gas supplier shall be notified when drip liquids are 
removed. 

4.3.2.2 Other Flammable Liquids. Flammable liquids used by 
the installer shall be handled with precaution and shall not be 
left within the premises from the end of one working day to 
the beginning of the next. 



Chapter 5 Gas Piping System Design, Materials, 
and Components 

5.1 Piping Plan. 

5.1.1 Installation of Piping System. Where required by the 
authority having jurisdiction, a piping sketch or plan shall be 
prepared before proceeding with the installation. This plan 
shall show the proposed location of piping, the size of differ- 
ent branches, the various load demands, and the location of 
the point of delivery. 

5.1.2 Addition to Existing System. 

5.1.2.1 When additional appliances are being connected to a 
gas piping system, the existing piping shall be checked to de- 
termine whether it has adequate capacity (see 5.4.3). 

5.1.2.2 If inadequate, the existing system shall be enlarged as 
required, or separate gas piping of adequate capacity shall be 
provided. 

5.2 Provision for Location of Point of Delivery. The location 
of the point of delivery shall be acceptable to the serving gas 
supplier. 

5.3 Interconnections Between Gas Piping Systems. 

5.3.1 Interconnections Supplying Separate Users. Where two 
or more meters, or two or more service regulators where 
meters are not provided, are located on the same premises 
and supply separate users, the gas piping systems shall not be 
interconnected on the outlet side of the meters or service 
regulators. 

5.3.2 Interconnections for Standby Fuels. 

5.3.2.1 Where a supplementary gas for standby use is con- 
nected downstream from a meter or a service regulator where 
a meter is not provided, equipment to prevent backflow shall 
be installed. 

5.3.2.2 A three-way valve installed to admit the standby supply 
and at the same time shut off the regular supply shall be per- 
mitted to be used for this purpose. 



5.4 Sizing of Gas Piping Systems. 

5.4.1* General Considerations. Gas piping systems shall be of 
such size and so installed as to provide a supply of gas suffi- 
cient to meet the maximum demand without undue loss of 
pressure between the point of delivery and the appliance. 

5.4.2* Maximum Gas Demand. 

5.4.2.1 The volume of gas to be provided (in cubic feet per 
hour) shall be determined directly from the manufacturers' in- 
put ratings of the appliances served. Where the input rating is not 
indicated, the gas supplier, appliance manufacturer, or a quali- 
fied agency shall be contacted, or the rating from Table 5.4.2.1 
shall be used for estimating the volume of gas to be supplied. 

5.4.2.2 The total connected hourly load shall be used as the 
basis for piping sizing, assuming all appliances are operating 
at full capacity simultaneously. 

Exception: Sizing shall be permitted to be based upon established load 
diversity factors. 



Table 5.4.2.1 Approximate Gas Input for 
Typical Appliances 



Appliance 



Input Btu/hr (Approx.) 



Space Heating Units 

Warm air furnace 



Single family 


100,000 


Multifamily, per unit 


60,000 


Hydronic boiler 




Single family 


100,000 


Multifamily, per unit 


60,000 


Space and Water Heating Units 




Hydronic boiler 




Single family 


120,000 


Multifamily, per unit 


75,000 


Water Heating Appliances 




Water heater, automatic storage 


35,000 


30 gal to 40 gal tank 




Water heater, automatic storage 


50,000 


50 gal tank 




Water heater, automatic 




instantaneous 




Capacity at 2 gal/min 


142,800 


Capacity at 4 gal/min 


285,000 


Capacity at 6 gal/min 


428,400 


Water heater, domestic, circulating 


35,000 


or side-arm 




Cooking Appliances 




Range, free standing, domestic 


65,000 


Built-in oven or broiler unit, 


25,000 


domestic 




Built-in top unit, domestic 


40,000 


Other Appliances 




Refrigerator 


3,000 


Clothes dryer, Type 1 (domestic) 


35,000 


Gas fireplace direct vent 


40,000 


Gas log 


80,000 


Barbecue 


40,000 


Gas light 


2,500 



For SI units, 1 Btu/hr = 0.293 W. 



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5.4.3* Sizing Methods. Gas piping shall be sized in accordance 
with one of the following: 

(1) Pipe sizing tables or sizing equations in Chapter 6 

(2) Other approved engineering methods acceptable to the 
authority having jurisdiction 

(3) Sizing tables included in a listed piping system manufac- 
turer's installation instructions 

5.4.4 Allowable Pressure Drop. The design pressure loss in 
any piping system under maximum probable flow conditions, 
from the point of delivery to the inlet connection of the appli- 
ance, shall be such that the supply pressure at the appliance is 
greater than the minimum pressure required for proper appli- 
ance operation. 

5.5 Piping System Operating Pressure limitations. 

5.5.1 Maximum Design Operating Pressure. The maximum 
design operating pressure for piping systems located inside 
buildings shall not exceed 5 psi (34 kPa) unless one or more of 
the following conditions are met: 

(l)*The piping system is welded. 

(2) The piping is located in a ventilated chase or otherwise en- 
closed for protection against accidental gas accumulation. 

(3) The piping is located inside buildings or separate areas of 
buildings used exclusively for one of the following: 

(a) Industrial processing or heating 

(b) Research 

(c) Warehousing 

(d) Boiler or mechanical rooms 

(4) The piping is a temporary installation for buildings under 
construction. 

5.5.2 Liquefied Petroleum Gas Systems. The operating pres- 
sure for undiluted LP-Gas systems shall not exceed 20 psi 
(140 kPa). Buildings having systems designed to operate be- 
low -5°F (-21 °C) or with butane or a propane-butane mix 
shall be designed to either accommodate liquid LP-Gas or pre- 
vent LP-Gas vapor from condensing back into a liquid. 

Exception: Buildings or separate areas of buildings constructed in 
accordance with Chapter 10 of NFPA 58, Liquefied Petroleum Gas 
Code, and used exclusively to house industrial processes, research and 
experimental laboratories, or equipment or processing having similar 
hazards. 

5.6 Acceptable Piping Materials and Joining Methods. 

5.6.1 General. 

5.6.1.1 Acceptable Materials. Materials used for piping sys- 
tems shall comply with the requirements of this chapter or 
shall be acceptable to the authority having jurisdiction. 

5.6.1.2 Used Materials. Pipe, fittings, valves, or other materials 
shall not be used again unless they are free of foreign materials 
and have been ascertained to be adequate for the service in- 
tended. 

5.6.1.3 Other Materials. Material not covered by the stan- 
dards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed 
service and, in addition, shall be recommended for that ser- 
vice by the manufacturer and shall be acceptable to the au- 
thority having jurisdiction. 

5.6.2 Metallic Pipe. 

5.6.2.1 Cast Iron. Cast-iron pipe shall not be used. 



5.6.2.2 Steel and Wrought Iron. Steel and wrought-iron pipe 
shall be at least of standard weight (Schedule 40) and shall 
comply with one of the following standards: 

(1) ANSI/ASME B36.10, Welded and Seamless WroughtSteel Pipe 

(2) ASTM A 53, Standard Specification for Pipe, Steel, Black and 
Hot-Dipped, Zinc-Coated Welded and Seamless 

(3) ASTM A 106, Standard Specification for Seamless Carbon Steel 
Pipe for High-Temperature Service 

5.6.2.3* Copper and Brass. Copper and brass pipe shall not be 
used if the gas contains more than an average of 0.3 grains of 
hydrogen sulfide per 100 scf of gas (0.7 mg/100 L). 

5.6.2.4 Threaded Copper, Brass, and Aluminum. Threaded 
copper, brass, or aluminum alloy pipe shall not be used with 
gases corrosive to such material. 

5.6.2.5 Aluminum Alloy. Aluminum alloy pipe shall comply 
with ASTM B 241, Specification for Aluminum-Alloy Seamless Pipe 
and Seamless Extruded Tube (except that the use of alloy 5456 is 
prohibited) and shall be marked at each end of each length 
indicating compliance. Aluminum alloy pipe shall be coated 
to protect against external corrosion where it is in contact with 
masonry, plaster, or insulation or is subject to repeated wet- 
tings by such liquids as water, detergents, or sewage. 

5.6.2.6 Aluminum Installation. Aluminum alloy pipe shall not 
be used in exterior locations or underground. 

5.6.3 Metallic Tubing. Seamless copper, aluminum alloy, or steel 
tubing shall not be used with gases corrosive to such material. 

5.6.3.1 Steel. Steel tubing shall comply with ASTM A 539, Stan- 
dard Specification for Electric Resistance-Welded Coiled Steel Tubing 
for Gas and Fuel Oil Lines, or ASTM A 254, Standard Specification 
for Copper Brazed Steel Tubing. 

5.6.3.2* Copper and Brass. Copper and brass tubing shall not 
be used if the gas contains more than an average of 0.3 grains of 
hydrogen sulfide per 100 scf of gas (0.7 mg/100 L). Copper tub- 
ing shall comply with standard Type K or Type L of ASTM B 88, 
Specification for Seamless Copper Water Tube, or ASTM B 280, Specifi- 
cation for Seamless Copper Tube for Air Conditioning and Refrigeration 
Field Service. 

5.6.3.3 Aluminum. Aluminum alloy tubing shall comply with 
ASTM B 210, Specification for Aluminum-Alloy Drawn Seamless Tubes, 
or ASTM B 241, Specification for Aluminum-Alloy Seamless Pipe and 
Seamless Extruded Tube. Aluminum alloy tubing shall be coated to 
protect against external corrosion where it is in contact with ma- 
sonry, plaster, or insulation or is subject to repeated wettings by 
such liquids as water, detergent, or sewage. Aluminum alloy tub- 
ing shall not be used in exterior locations or underground. 

5.6.3.4 Corrugated Stainless Steel. Corrugated stainless steel 
tubing shall be listed in accordance with ANSI LC 1/CSA6.26, 
Fuel Gas Piping Systems Using Corrugated Stainless Steel Tubing. 

5.6.4 Plastic Pipe, Tubing, and Fittings. 

5.6.4.1 Plastic pipe, tubing, and fittings used to supply fuel 
gas shall be used outdoors underground only and shall con- 
form to ASTM D 2513, Standard Specification for Thermoplastic 
Gas Pressure Pipe, Tubing, and Fittings. Pipe to be used shall be 
marked "gas" and "ASTM D 251 3." 

5.6.4.2* Regulator Vent Piping. Plasdc pipe, tubing, and fit- 
tings used to connect regulator vents to remote vent termina- 
tions shall be PVC conforming to UL 651, Schedule 40 and 



2006 Edition 



ANSIZ223.1-19 



GAS PIPING SYSTEM DESIGN, MATERIALS, AND COMPONENTS 



54-19 



Schedule 80 Rigid PVC Conduit. PVC vent piping shall not be 
installed indoors. 

5.6.4.3 Anodeless Risers. Anodeless risers shall comply with 
the following: 

(1) Factory-assembled anodeless risers shall be recommended 
by the manufacturer for the gas used and shall be leak tested 
by the manufacturer in accordance with written procedures. 

(2) Service head adapters and field-assembled anodeless ris- 
ers incorporating service head adapters shall be recom- 
mended by the manufacturer for the gas used and shall be 
design-certified to meet the requirements of Category I of 
ASTM D 2513, Standard Specification for Thermoplastic Gas 
Pressure Pipe, Tubing, and Fittings, and 49 CFR 192.281(e). 
The manufacturer shall provide the user qualified instal- 
lation instructions as prescribed by 49 CFR 192.283(b). 

(3) The use of plastic pipe, tubing, and fittings in undiluted 
liquefied petroleum gas piping systems shall be in accor- 
dance with NFPA 58, Liquefied Petroleum Gas Code. 

5.6.5 Workmanship and Defects. Gas pipe, tubing, and fit- 
tings shall be clear and free from cutting burrs and defects in 
structure or threading and shall be thoroughly brushed and 
chip and scale blown. Defects in pipe, tubing, and fittings shall 
not be repaired. Defective pipe, tubing, and fittings shall be 
replaced. (See 8.1.1.3.) 

5.6.6 Protective Coating. Where in contact with material or 
atmosphere exerting a corrosive action, metallic piping and 
fittings coated with a corrosion-resistant material shall be 
used. External or internal coatings or linings used on piping 
or components shall not be considered as adding strength. 

5.6.7 Metallic Pipe Threads. 

5.6.7.1 Specifications for Pipe Threads. Metallic pipe and fit- 
ting threads shall be taper pipe threads and shall comply with 
ANSI/ASME Bl.20.1, Pipe Threads, General Purpose, Inch. 

5.6.7.2 Damaged Threads. Pipe with threads that are 
stripped, chipped, corroded, or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting 
or threading, that portion of the pipe shall not be used. 

5.6.7.3 Number of Threads. Field threading of metallic pipe 
shall be in accordance with Table 5.6.7.3. 



Table 5.6.7.3 Specifications for Threading 
Metallic Pipe 



Iron Pipe 
Size 
(in.) 



Approximate 

Length of 

Threaded Portion 

(in.) 



Approximate 

No. of Threads 

to Be Cut 



V2 


3 /4 


10 


% 


¥4 


10 


1 


% 


10 


1V4 ] 




11 


IV2 ] 




11 


2 1 




11 


2% 


Wi 


12 


3 


LV& 


12 


4 


1 5/8 


13 



5.6.7.4 Thread Compounds. Thread (joint) compounds (pipe 
dope) shall be resistant to the action of liquefied petroleum gas 
or to any other chemical constituents of the gases to be con- 
ducted through the piping. 

5.6.8 Metallic Piping Joints and Fittings. The type of piping 
joint used shall be suitable for the pressure-temperature con- 
ditions and shall be selected giving consideration to joint 
tightness and mechanical strength under the service condi- 
tions. The joint shall be able to sustain the maximum end 
force due to the internal pressure and any additional forces 
due to temperature expansion or contraction, vibration, fa- 
tigue, or the weight of the pipe and its contents. 

5.6.8.1* Pipe Joints. Pipe joints shall be threaded, flanged, 
brazed, or welded. Where nonferrous pipe is brazed, the braz- 
ing materials shall have a melting point in excess of 1000°F 
(538°C) . Brazing alloys shall not contain more than 0.05 per- 
cent phosphorus. 

5.6.8.2 Tubing Joints. Tubingjoints shall either be made with 
approved gas tubing fittings or be brazed with a material hav- 
ing a melting point in excess of 1000°F (538°C) . Brazing alloys 
shall not contain more than 0.05 percent phosphorus. 

5.6.8.3 Flared Joints. Flared joints shall be used only in sys- 
tems constructed from nonferrous pipe and tubing where ex- 
perience or tests have demonstrated that the joint is suitable 
for the conditions and where provisions are made in the de- 
sign to prevent separation of the joints. 

5.6.8.4 Metallic Fittings (Including Valves, Strainers, Filters). 

Metallic fittings shall comply with the following: 



(1) 



(2) 
(3) 
(4) 
(5) 



(6) 

(7) 

(8) 



For SI units, 1 in. = 25.4 mm. 



Threaded fittings in sizes larger than 4 in. (100 mm) shall 
not be used unless acceptable to the authority having ju- 
risdiction. 

Fittings used with steel or wrought-iron pipe shall be steel, 
brass, bronze, malleable iron, or cast iron. 
Fittings used with copper or brass pipe shall be copper, 
brass, or bronze. 

Fittings used with aluminum alloy pipe shall be of alumi- 
num alloy. 

Cast-iron Fittings. Cast-iron fittings shall comply with the 
following: 

(a) Flanges shall be permitted. 

(b) Bushings shall not be used. 

(c) Fittings shall not be used in systems containing flam- 
mable gas-air mixtures. 

(d) Fittings in sizes 4 in. (100 mm) and larger shall not be 
used indoors unless approved by the authority having 
jurisdiction. 

(e) Fittings in sizes 6 in. (150 mm) and larger shall not be 
used unless approved by the authority having 
jurisdiction. 

Aluminum Alloy Fittings. Threads shall not form the joint seal. 
Zinc-Aluminum Alloy Fittings. Fittings shall not be used in 
systems containing flammable gas-air mixtures. 
Special Fittings. Fittings such as couplings, proprietary-type 
joints, saddle tees, gland-type compression fittings, and 
flared, flareless, or compression-type tubing fittings shall 
be (1) used within the fitting manufacturer's pressure- 
temperature recommendations; (2) used within the ser- 
vice conditions anticipated with respect to vibration, fa- 
tigue, thermal expansion, or contraction; (3) installed or 
braced to prevent separation of the joint by gas pressure 
or external physical damage; and (4) acceptable to the 
authority havingjurisdiction. 



2006 Edition 



54-20 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-20 



5.6.9 Plastic Piping, Joints, and Fittings. Plastic pipe, tubing, 
and fittings shall be joined in accordance with the manufac- 
turers' instructions. The following shall be observed when 
making such joints: 

(1) The joint shall be designed and installed so that the lon- 
gitudinal pullout resistance of the joint will be at least 
equal to the tensile strength of the plastic piping material. 

(2) Heat-fusion joints shall be made in accordance with quali- 
fied procedures that have been established and proven by 
test to produce gastight joints at least as strong as the pipe 
or tubing being joined. Joints shall be made with the join- 
ing method recommended by the pipe manufacturer. 
Heat fusion fittings shall be marked "ASTM D 2513." 

(3) Where compression-type mechanical joints are used, the 
gasket material in the fitting shall be compatible with the 
plastic piping and with the gas distributed by the system. 
An internal tubular rigid stiffener shall be used in con- 
junction with the fitting. The stiffener shall be flush with 
the end of the pipe or tubing and shall extend at least to 
the outside end of the compression fitting when installed. 
The stiffener shall be free of rough or sharp edges and 
shall not be a force fit in the plastic. Split tubular stiffeners 
shall not be used. 

(4) Plastic piping joints and fittings for use in liquefied petro- 
leum gas piping systems shall be in accordance with 
NFPA 58, Liquefied Petroleum Gas Code. 

5.6.10 Flanges. All flanges shall comply with ANSI/ASME 
B16.1, Cast Iron Pipe Flanges and Hanged Fittings, Class 25, 125, 
250, and 800, ANSI/ASME B16.20, Metal Gaskets for Pipe 
Flanges, Ringjoint Spiral Wound andfacketed; or MSS SP-6, Stan- 
dard Finishes for Contact Faces of Pipe Flanges and Connecting-End 
Flanges of Valves and Fittings. The pressure-temperature ratings 
shall equal or exceed that required by the application. 

5.6.10.1 Flange Facings. Standard facings shall be permitted 
for use under this code. Where 1 50 psi ( 1 034 kPa) steel flanges 
are bolted to Class 125 cast-iron flanges, the raised face on the 
steel flange shall be removed. 

5.6.10.2 Lapped Flanges. Lapped flanges shall be used only 
aboveground or in exposed locations accessible for inspection. 

5.6.11 Flange Gaskets. The material for gaskets shall be ca- 
pable of withstanding the design temperature and pressure of 
the piping system and the chemical constituents of the gas 
being conducted without change to its chemical and physical 
properties. The effects of fire exposure to the joint shall be 
considered in choosing the material. 

5.6.11.1 Acceptable materials shall include the following: 

(1) Metal or metal-jacketed asbestos (plain or corrugated) 

(2) Asbestos 

(3) Aluminum "O" rings and spiral-wound metal gaskets 

5.6.11.2 When a flanged joint is opened, the gasket shall be 
replaced. 

5.6.11.3 Full-face gaskets shall be used with all bronze and 
cast-iron flanges. 

5.7* Gas Meters. 

5.7.1 Capacity. Gas meters shall be selected for the maximum 
expected pressure and permissible pressure drop. 

5.7.2 Location. 

5.7.2.1 Gas meters shall be located in ventilated spaces 
readily accessible for examination, reading, replacement, or 
necessary maintenance. 



5.7.2.2 Gas meters shall not be placed where they will be 
subjected to damage, such as adjacent to a driveway, under a 
fire escape, in public passages, halls, or coal bins, or where 
they will be subject to excessive corrosion or vibration. 

5.7.2.3 Gas meters shall be located at least 3 ft (0.9 m) from 
sources of ignition. 

5.7.2.4 Gas meters shall not be located where they will be 
subjected to extreme temperatures or sudden extreme 
changes in temperature. Meters shall not be located in areas 
where they are subjected to temperatures beyond those rec- 
ommended by the manufacturer. 

5.7.3 Supports. Gas meters shall be supported or connected 
to rigid piping so as not to exert a strain on the meters. Where 
flexible connectors are used to connect a gas meter to down- 
stream piping at mobile homes in mobile home parks, the 
meter shall be supported by a post or bracket placed in a firm 
footing or by other means providing equivalent support. 

5.7.4 Meter Protection. Meters shall be protected against 
overpressure, back pressure, and vacuum, where such condi- 
tions are anticipated. 

5.7.5 Identification. Gas piping at multiple meter installations 
shall be marked by a metal tag or other permanent means desig- 
nating the building or the part of the building being supplied 
and attached by the installing agency. 

5.8* Gas Pressure Regulators. 

5.8.1 Where Required. A line gas pressure regulator or gas 
equipment pressure regulator, as applicable, shall be installed 
where the gas supply pressure is higher than that at which the 
branch supply line or appliances are designed to operate or 
vary beyond design pressure limits. 

5.8.2 Line gas pressure regulators shall be listed in accor- 
dance with ANSI Z21.80, Line Pressure Regulators. 

5.8.3 Location. The gas pressure regulator shall be accessible 
for servicing. 

5.8.4 Regulator Protection. Pressure regulators shall be pro- 
tected against physical damage. 

5.8.5 Venting. 

5.8.5.1 Line Gas Pressure Regulators. Line gas pressure regu- 
lators shall comply with the following: 

( 1 ) An independent vent to the exterior of the building, sized 
in accordance with the regulator manufacturer's instruc- 
tions, shall be provided where the location of a regulator 
is such that a ruptured diaphragm will cause a hazard. 

(a) Where there is more than one regulator at a location, 
each regulator shall have a separate vent to the out- 
doors, or if approved by the authority having jurisdic- 
tion, the vent lines shall be permitted to be mani- 
folded in accordance with accepted engineering 
practices to minimize back pressure in the event of 
diaphragm failure. (See 5. 9. 7 for information on properly 
locating the vent.) 

(b) Materials for vent piping shall be in accordance with 
Section 5.6. 

Exception: A regulator and vent limiting means combination listed 
as complying with ANSI Z21.80, Line Pressure Regulators, shall be 
permitted to be used without a vent to the outdoors. 



2006 Edition 



ANSI Z223.1-21 



GAS PIPING SYSTEM DESIGN, MATERIALS, AND COMPONENTS 



54-21 



(2) The vent shall be designed to prevent the entry of water, 
insects, or other foreign materials that could cause blockage. 

(3) At locations where regulators might be submerged during 
floods, a special antiflood-type breather vent fitting shall 
be installed, or the vent line shall be extended above the 
height of the expected flood waters. 

(4) A regulator shall not be vented to the appliance flue or 
exhaust system. 

5.8.5.2 Appliance Pressure Regulators. For venting of gas ap- 
pliance pressure regulators, see 9.1.19. 

5.8.6 Bypass Piping. Valved and regulated bypasses shall be 
permitted to be placed around gas line pressure regulators 
where continuity of service is imperative. 

5.8.7 Identification. Line pressure regulators at multiple 
regulator installations shall be marked by a metal tag or other 
permanent means designating the building or the part of the 
building being supplied. 

5.9 Overpressure Protection Devices. 

5.9.1 General. Overpressure protection devices shall be pro- 
vided to prevent the pressure in the piping system from ex- 
ceeding that value that would cause unsafe operation of any 
connected and properly adjusted appliances. (See 5.9.5.) 

5.9.1.1 The requirements of this section shall be met and a 
piping system deemed to have overpressure protection where 
a service or line pressure regulator plus one other device are 
installed such that the following occur: 

(1) Each device limits the pressure to a value that does not 
exceed the maximum working pressure of the down- 
stream system. 

(2) The individual failure of either device does not result in 
overpressure of the downstream system. 

5.9.1.2 The pressure regulating, limiting, and relieving de- 
vices shall be properly maintained, inspection procedures 
shall be devised or suitable instrumentation installed to detect 
failures or malfunctions of such devices, and replacements or 
repairs shall be promptly made. 

5.9.1.3 A pressure relieving or limiting device shall not be 
required where (1) the gas does not contain materials that 
could seriously interfere with the operation of the service or 
line pressure regulator; (2) the operating pressure of the gas 
source is 60 psi (414 kPa) or less; and (3) the service or line 
pressure regulator has all of the following design features or 
characteristics: 

(1) Pipe connections to the service or line regulator do not 
exceed 2-in. nominal diameter. 

(2) The regulator is self-contained with no external static or 
control piping. 

(3) The regulator has a single port valve with an orifice diam- 
eter no greater than that recommended by the manufac- 
turer for the maximum gas pressure at the regulator inlet. 

(4) The valve seat is made of resilient material designed to 
withstand abrasion of the gas, impurities in the gas, and 
cutting by the valve and to resist permanent deformation 
where it is pressed against the valve port. 

(5) The regulator is capable, under normal operating condi- 
tions, of regulating the downstream pressure within the 
necessary limits of accuracy and of limiting the discharge 
pressure under no-flow conditions to not more than 
150 percent of the discharge pressure maintained under 
flow conditions. 



5.9.2 Devices. 

5.9.2.1 Pressure relieving or pressure limiting devices shall be 
one of the following: 

(1) Spring-loaded relief device 

(2) Pilot-loaded back pressure regulator used as a relief valve 
so designed that failure of the pilot system or external 
control piping will cause the regulator relief valve to open 

(3) A monitoring regulator installed in series with the service 
or line pressure regulator 

(4) A series regulator installed upstream from the service or 
line regulator and set to continuously limit the pressure 
on the inlet of the service or line regulator to the maxi- 
mum working pressure of the downstream piping system 

(5) An automatic shutoff device installed in series with the 
service or line pressure regulator and set to shut off when 
the pressure on the downstream piping system reaches 
the maximum working pressure or some other predeter- 
mined pressure less than the maximum working pressure 
This device shall be designed so that it will remain closed 
until manually reset. 

(6) A liquid seal relief device that can be set to open accu- 
rately and consistently at the desired pressure 

5.9.2.2 The devices in 5.9.2.1 shall be installed either as an 
integral part of the service or line pressure regulator or as 
separate units. Where separate pressure relieving or pressure 
limiting devices are installed, they shall comply with 5.9.3 
through 5.9.8. 

5.9.3 Construction and Installation. All pressure relieving or 
pressure limiting devices shall meet the following requirements: 

(1) Be constructed of materials so that the operation of the 
device will not be impaired by corrosion of external parts 
by the atmosphere or of internal parts by the gas. 

(2) Be designed and installed so they can be operated to de- 
termine whether the valve is free. The devices shall also be 
designed and installed so they can be tested to determine 
the pressure at which they will operate and be examined 
for leakage when in the closed position. 

5.9.4 External Control Piping. External control piping shall 
be protected from falling objects, excavations, or other causes 
of damage and shall be designed and installed so that damage 
to any control piping shall not render both the regulator and 
the overpressure protective device inoperative. 

5.9.5 Setting. Each pressure limiting or pressure relieving de- 
vice shall be set so that the pressure shall not exceed a safe 
level beyond the maximum allowable working pressure for the 
piping and appliances connected. 

5.9.6 Unauthorized Operation. Precautions shall be taken to 
prevent unauthorized operation of any shutoff valve that will 
make a pressure relieving valve or pressure limiting device in- 
operative. The following are acceptable methods for comply- 
ing with this provision: 

(1) Lock the valve in the open position. Instruct authorized 
personnel in the importance of leaving the shutoff valve 
open and of being present while the shutoff valve is closed 
so that it can be locked in the open position before leav- 
ing the premises. 

(2) Install duplicate relief valves, each having adequate capac- 
ity to protect the system, and arrange the isolating valves 
or three-way valve so that only one safety device can be 
rendered inoperative at a time. 



2006 Edition 



54-22 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-22 



5.9.7 Vents. 

5.9.7.1 The discharge stacks, vents, or outlet parts of all pres- 
sure relieving and pressure limiting devices shall be located so 
that gas is safely discharged to the outdoors. Discharge stacks 
or vents shall be designed to prevent the entry of water, in- 
sects, or other foreign material that could cause blockage. 

5.9.7.2 The discharge stack or vent line shall be at least the 
same size as the outlet of the pressure relieving device. 

5.9.8 Size of Fittings, Pipe, and Openings. The fittings, pipe, 
and openings located between the system to be protected 
and the pressure relieving device shall be sized to prevent 
hammering of the valve and to prevent impairment of relief 
capacity. 

5.10 Back Pressure Protection. 

5.10.1 Where to Install. 

5.10.1.1 Protective devices shall be installed as close to the 
equipment as practical where the design of equipment con- 
nected is such that air, oxygen, or standby gases could be 
forced into the gas supply system. 

5.10.1.2 Gas and air combustion mixers incorporating double 
diaphragm "zero" or "atmosphere" governors or regulators shall 
require no further protection unless connected directly to com- 
pressed air or oxygen at pressures of 5 psi (34 kPa) or more. 

5.10.2 Protective Devices. Protective devices shall include but 
not be limited to the following: 

( 1 ) Check valves 

(2) Three-way valves (of the type that completely closes one 
side before starting to open the other side) 

(3) Reverse flow indicators controlling positive shutoff valves 

(4) Normally closed air-actuated positive shutoff pressure 
regulators 

5.11 Low-Pressure Protection. A protective device shall be in- 
stalled between the meter and the appliance if the operation 
of the appliance is such (i.e., gas compressors) that it could 
produce a vacuum or a dangerous reduction in gas pressure at 
the meter; such devices include, but are not limited to, me- 
chanical, diaphragm-operated, or electrically operated low- 
pressure shutoff valves. 

5.12 Shutoff Valves. Shutoff valves shall be approved and shall 
be selected giving consideration to pressure drop, service in- 
volved, emergency use, and reliability of operation. Shutoff 
valves of size 1 in. National Pipe Thread and smaller shall be 
listed. 

5.13 Expansion and Flexibility. 

5.13.1 Design. Piping systems shall be designed to have suffi- 
cient flexibility to prevent thermal expansion or contraction 
from causing excessive stresses in the piping material, exces- 
sive bending or loads at joints, or undesirable forces or mo- 
ments at points of connections to appliances and equipment 
and at anchorage or guide points. Formal calculations or 
model tests shall be required only where reasonable doubt 
exists as to the adequate flexibility of the system. 



5.13.1.1 Flexibility shall be provided by the use of bends, 
loops, offsets, or couplings of the slip type. Provision shall be 
made to absorb thermal changes by the use of expansion 
joints of the bellows type or by the use of "ball" or "swivel" 
joints. Expansion joints of the slip type shall not be used inside 
buildings or for thermal expansion. Where expansion joints 
are used, anchors or ties of sufficient strength and rigidity 
shall be installed to provide for end forces due to fluid pres- 
sure and other causes. 

5.13.1.2 Pipe alignment guides shall be used with expansion 
joints according to the recommended practice of the joint 
manufacturer. 

5.13.2 Special Local Conditions. Where local conditions in- 
clude earthquake, tornado, unstable ground, or flood haz- 
ards, special consideration shall be given to increased strength 
and flexibility of piping supports and connections. 



Chapter 6 Pipe Sizing 

6.1 Pipe Sizing Methods. Where the pipe size is to be deter- 
mined using any of the methods in 6.1.1 through 6.1.3, the 
diameter of each pipe segment shall be obtained from the 
pipe sizing tables in Section 6.2 or from the sizing equations in 
Section 6.4. (See calculation examples in Annex C.) For SI units, 
1 ft 3 = 0.028 m 3 , 1 ft = 0.305 m, 1 in. w.c. = 0.249 kPa, 1 psi = 
6.894 kPa, 1000 Btu/hr = 0.293 kW 

6.1.1* Longest Length Method. The pipe size of each section 
of gas piping shall be determined using the longest length of 
piping from the point of delivery to the most remote outlet 
and the load of the section. 

6.1.2* Branch Length Method. Pipe shall be sized as follows: 

(1) Pipe size of each section of the longest pipe run from the 
point of delivery to the most remote oudet shall be deter- 
mined using the longest run of piping and the load of the 
section. 

(2) The pipe size of each section of branch piping not previ- 
ously sized shall be determined using the length of piping 
from the point of delivery to the most remote outlet in 
each branch and the load of the section. 

6.1.3 Hybrid Pressure. The pipe size for each section of 
higher pressure gas piping shall be determined using the 
longest length of piping from the point of delivery to the most 
remote line pressure regulator. The pipe size from the line 
pressure regulator to each outlet shall be determined using 
the length of piping from the regulator to the most remote 
outlet served by the regulator. 

6.2 Tables for Sizing Gas Piping Systems Using Natural Gas. 

Table 6.2(a) through Table 6.2 (v) shall be used to size gas 
piping in conjunction with one of the methods described in 
6.1.1 through 6.1.3. 

6.3 Tables for Sizing Gas Piping Systems Using Propane. 

Table 6.3(a) through Table 6.3 (m) shall be used to size gas 
piping in conjunction with one of the methods described in 
6.1.1 through 6.1.3. 



2006 Edition 



ANSI Z223. 1-23 



PIPE SIZING 



54-23 



Table 6.2(a) Schedule 40 Metallic Pipe 

























Gas: 


Natural 




Inlet Pressure: 


Less than 1 


jsi 




Pressure Drop: 


0.3 in. w.c. 




Specific Gravity: 


0.60 
















Pipe Size (in 


•) 












Nominal: 


'/2 


% 


1 


l'/4 


l'/2 


2 


2'/2 


3 


4 


5 


6 


8 


10 


12 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


5.047 


6.065 


7.981 


10.020 


11.938 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


131 


273 


514 


1,060 


1,580 


3,050 


4,860 


8,580 


17,500 


31,700 


51,300 


105,000 


191,000 


303,000 


20 


90 


188 


353 


726 


1,090 


2,090 


3,340 


5,900 


12,000 


21,800 


35,300 


72,400 


132,000 


208,000 


30 


72 


151 


284 


583 


873 


1,680 


2,680 


4,740 


9,660 


17,500 


28,300 


58,200 


106,000 


167,000 


40 


62 


129 


243 


499 


747 


1,440 


2,290 


4,050 


8,270 


15,000 


24,200 


49,800 


90,400 


143,000 


50 


55 


114 


215 


442 


662 


1,280 


2,030 


3,590 


7,330 


13,300 


21,500 


44,100 


80,100 


127,000 


60 


50 


104 


195 


400 


600 


1,160 


1,840 


3,260 


6,640 


12,000 


19,500 


40,000 


72,600 


115,000 


70 


46 


95 


179 


368 


552 


1,060 


1,690 


3,000 


6,110 


11,100 


17,900 


36,800 


66,800 


106,000 


80 


42 


89 


167 


343 


514 


989 


1,580 


2,790 


5,680 


10,300 


16,700 


34,200 


62,100 


98,400 


90 


40 


83 


157 


322 


482 


928 


1,480 


2,610 


5,330 


9,650 


15,600 


32,100 


58,300 


92,300 


100 


38 


79 


148 


304 


455 


877 


1,400 


2,470 


5,040 


9,110 


14,800 


30,300 


55,100 


87,200 


125 


33 


70 


131 


269 


403 


777 


1,240 


2,190 


4,460 


8,080 


13,100 


26,900 


48,800 


77,300 


150 


30 


63 


119 


244 


366 


704 


1,120 


1,980 


4,050 


7,320 


11,900 


24,300 


44,200 


70,000 


175 


28 


58 


109 


224 


336 


648 


1,030 


1,820 


3,720 


6,730 


10,900 


22,400 


40,700 


64,400 


200 


26 


54 


102 


209 


313 


602 


960 


1,700 


3,460 


6,260 


10,100 


20,800 


37,900 


59,900 


250 


23 


48 


90 


185 


277 


534 


851 


1,500 


3,070 


5,550 


8,990 


18,500 


33,500 


53,100 


300 


21 


43 


82 


168 


251 


484 


771 


1,360 


2,780 


5,030 


8,150 


16,700 


30,400 


48,100 


350 


19 


40 


75 


154 


231 


445 


709 


1,250 


2,560 


4,630 


7,490 


15,400 


28,000 


44,300 


400 


18 


37 


70 


143 


215 


414 


660 


1,170 


2,380 


4,310 


6,970 


14,300 


26,000 


41,200 


450 


17 


35 


66 


135 


202 


389 


619 


1,090 


2,230 


4,040 


6,540 


13,400 


24,400 


38,600 


500 


16 


33 


62 


127 


191 


367 


585 


1,030 


2,110 


3,820 


6,180 


12,700 


23,100 


36,500 


550 


15 


31 


59 


121 


181 


349 


556 


982 


2,000 


3,620 


5,870 


12,100 


21,900 


34,700 


600 


14 


30 


56 


115 


173 


333 


530 


937 


1,910 


3,460 


5,600 


11,500 


20,900 


33,100 


650 


14 


29 


54 


110 


165 


318 


508 


897 


1,830 


3,310 


5,360 


11,000 


20,000 


31,700 


700 


13 


27 


52 


106 


159 


306 


488 


862 


1,760 


3,180 


5,150 


10,600 


19,200 


30,400 


750 


13 


26 


50 


102 


153 


295 


470 


830 


1,690 


3,060 


4,960 


10,200 


18,500 


29,300 


800 


12 


26 


48 


99 


148 


285 


454 


802 


1,640 


2,960 


4,790 


9,840 


17,900 


28,300 


850 


12 


25 


46 


95 


143 


275 


439 


776 


1,580 


2,860 


4,640 


9,530 


17,300 


27,400 


900 


11 


24 


45 


93 


139 


267 


426 


752 


1,530 


2,780 


4,500 


9,240 


16,800 


26,600 


950 


11 


23 


44 


90 


135 


259 


413 


731 


1,490 


2,700 


4,370 


8,970 


16,300 


25,800 


1,000 


11 


23 


43 


87 


131 


252 


402 


711 


1,450 


2,620 


4,250 


8,720 


15,800 


25,100 


1,100 


10 


21 


40 


83 


124 


240 


382 


675 


1,380 


2,490 


4,030 


8,290 


15,100 


23,800 


1,200 


NA 


20 


39 


79 


119 


229 


364 


644 


1,310 


2,380 


3,850 


7,910 


14,400 


22,700 


1,300 


NA 


20 


37 


76 


114 


219 


349 


617 


1,260 


2,280 


3,680 


7,570 


13,700 


21,800 


1,400 


NA 


19 


35 


73 


109 


210 


335 


592 


1,210 


2,190 


3,540 


7,270 


13,200 


20,900 


1,500 


NA 


18 


34 


70 


105 


203 


323 


571 


1,160 


2,110 


3,410 


7,010 


12,700 


20,100 


1,600 


NA 


18 


33 


68 


102 


196 


312 


551 


1,120 


2,030 


3,290 


6,770 


12,300 


19,500 


1,700 


NA 


17 


32 


66 


98 


189 


302 


533 


1,090 


1,970 


3,190 


6,550 


11,900 


18,800 


1,800 


NA 


16 


31 


64 


95 


184 


293 


517 


1,050 


1,910 


3,090 


6,350 


11,500 


18,300 


1,900 


NA 


16 


30 


62 


93 


178 


284 


502 


1,020 


1,850 


3,000 


6,170 


11,200 


17,700 


2,000 


NA 


16 


29 


60 


90 


173 


276 


488 


1,000 


1,800 


2,920 


6,000 


10,900 


17,200 



NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-24 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-24 



Table 6.2(b) Schedule 40 Metallic Pipe 

























Gas: 


Natural 




Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal: 


Vl 


V* 


1 


l'/4 


1V4 


2 


2'/2 


3 


4 


5 


6 


8 


10 


12 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


5.047 


6.065 


7.981 


10.020 


11.938 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


172 


360 


678 


1,390 


2,090 


4,020 


6,400 


11,300 


23,100 


41,800 


67,600 


139,000 


252,000 


399,000 


20 


118 


247 


466 


957 


1,430 


2,760 


4,400 


7,780 


15,900 


28,700 


46,500 


95,500 


173,000 


275,000 


30 


95 


199 


374 


768 


1,150 


2,220 


3,530 


6,250 


12,700 


23,000 


37,300 


76,700 


139,000 


220,000 


40 


81 


170 


320 


657 


985 


1,900 


3,020 


5,350 


10,900 


19,700 


31,900 


65,600 


119,000 


189,000 


50 


72 


151 


284 


583 


873 


1,680 


2,680 


4,740 


9,660 


17,500 


28,300 


58,200 


106,000 


167,000 


60 


65 


137 


257 


528 


791 


1,520 


2,430 


4,290 


8,760 


15,800 


25,600 


52,700 


95,700 


152,000 


70 


60 


126 


237 


486 


728 


1,400 


2,230 


3,950 


8,050 


14,600 


23,600 


48,500 


88,100 


139,000 


80 


56 


117 


220 


452 


677 


1,300 


2,080 


3,670 


7,490 


13,600 


22,000 


45,100 


81,900 


130,000 


90 


52 


110 


207 


424 


635 


1,220 


1,950 


3,450 


7,030 


12,700 


20,600 


42,300 


76,900 


122,000 


100 


50 


104 


195 


400 


600 


1,160 


1,840 


3,260 


6,640 


12,000 


19,500 


40,000 


72,600 


115,000 


125 


44 


92 


173 


355 


532 


1,020 


1,630 


2,890 


5,890 


10,600 


17,200 


35,400 


64,300 


102,000 


150 


40 


83 


157 


322 


482 


928 


1,480 


2,610 


5,330 


9,650 


15,600 


32,100 


58,300 


92,300 


175 


37 


77 


144 


296 


443 


854 


1,360 


2,410 


4,910 


8,880 


14,400 


29,500 


53,600 


84,900 


200 


34 


71 


134 


275 


412 


794 


1,270 


2,240 


4,560 


8,260 


13,400 


27,500 


49,900 


79,000 


250 


30 


63 


119 


244 


366 


704 


1,120 


1,980 


4,050 


7,320 


11,900 


24,300 


44,200 


70,000 


300 


27 


57 


108 


221 


331 


638 


1,020 


1,800 


3,670 


6,630 


10,700 


22,100 


40,100 


63,400 


350 


25 


53 


99 


203 


305 


587 


935 


1,650 


3,370 


6,100 


9,880 


20,300 


36,900 


58,400 


400 


23 


49 


92 


189 


283 


546 


870 


1,540 


3,140 


5,680 


9,190 


18,900 


34,300 


54,300 


450 


22 


46 


86 


177 


266 


512 


816 


1,440 


2,940 


5,330 


8,620 


17,700 


32,200 


50,900 


500 


21 


43 


82 


168 


251 


484 


771 


1,360 


2,780 


5,030 


8,150 


16,700 


30,400 


48,100 


550 


20 


41 


78 


159 


239 


459 


732 


1,290 


2,640 


4,780 


7,740 


15,900 


28,900 


45,700 


600 


19 


39 


74 


152 


228 


438 


699 


1,240 


2,520 


4,560 


7,380 


15,200 


27,500 


43,600 


650 


18 


38 


71 


145 


218 


420 


669 


1,180 


2,410 


4,360 


7,070 


14,500 


26,400 


41,800 


700 


17 


36 


68 


140 


209 


403 


643 


1,140 


2,320 


4,190 


6,790 


14,000 


25,300 


40,100 


750 


17 


35 


66 


135 


202 


389 


619 


1,090 


2,230 


4,040 


6,540 


13,400 


24,400 


38,600 


800 


16 


34 


63 


130 


195 


375 


598 


1,060 


2,160 


3,900 


6,320 


13,000 


23,600 


37,300 


850 


16 


33 


61 


126 


189 


363 


579 


1,020 


2,090 


3,780 


6,110 


12,600 


22,800 


36,100 


900 


15 


32 


59 


122 


183 


352 


561 


992 


2,020 


3,660 


5,930 


12,200 


22,100 


35,000 


950 


15 


31 


58 


118 


178 


342 


545 


963 


1,960 


3,550 


5,760 


11,800 


21,500 


34,000 


1,000 


14 


30 


56 


115 


173 


333 


530 


937 


1,910 


3,460 


5,600 


11,500 


20,900 


33,100 


1,100 


14 


28 


53 


109 


164 


316 


503 


890 


1,810 


3,280 


5,320 


10,900 


19,800 


31,400 


1,200 


13 


27 


51 


104 


156 


301 


480 


849 


1,730 


3,130 


5,070 


10,400 


18,900 


30,000 


1,300 


12 


26 


49 


100 


150 


289 


460 


813 


1,660 


3,000 


4,860 


9,980 


18,100 


28,700 


1,400 


12 


25 


47 


96 


144 


277 


442 


781 


1,590 


2,880 


4,670 


9,590 


17,400 


27,600 


1,500 


11 


24 


45 


93 


139 


267 


426 


752 


1,530 


2,780 


4,500 


9,240 


16,800 


26,600 


1,600 


11 


23 


44 


89 


134 


258 


411 


727 


1,480 


2,680 


4,340 


8,920 


16,200 


25,600 


1,700 


11 


22 


42 


86 


130 


250 


398 


703 


1,430 


2,590 


4,200 


8,630 


15,700 


24,800 


1,800 


10 


22 


41 


84 


126 


242 


386 


682 


1,390 


2,520 


4,070 


8,370 


15,200 


24,100 


1,900 


10 


21 


40 


81 


122 


235 


375 


662 


1,350 


2,440 


3,960 


8,130 


14,800 


23,400 


2,000 


NA 


20 


39 


79 


119 


229 


364 


644 


1,310 


2,380 


3,850 


7,910 


14,400 


22,700 



NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223. 1-25 



PIPE SIZING 



54-25 



Table 6.2(c) Schedule 40 Metallic Pipe 















Gas: 


Natural 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal: 


l A 


V* 


1 


1*4 


VA 


2 


2*4 


3 


4 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in 


Cubic Feet of Gas per Hour 








10 


1,510 


3,040 


5,560 


11,400 


17,100 


32,900 


52,500 


92,800 


189,000 


20 


1,070 


2,150 


3,930 


8,070 


12,100 


23,300 


37,100 


65,600 


134,000 


30 


869 


1,760 


3,210 


6,590 


9,880 


19,000 


30,300 


53,600 


109,000 


40 


753 


1,520 


2,780 


5,710 


8,550 


16,500 


26,300 


46,400 


94,700 


50 


673 


1,360 


2,490 


5,110 


7,650 


14,700 


23,500 


41,500 


84,700 


60 


615 


1,240 


2,270 


4,660 


6,980 


13,500 


21,400 


37,900 


77,300 


70 


569 


1,150 


2,100 


4,320 


6,470 


12,500 


19,900 


35,100 


71,600 


80 


532 


1,080 


1,970 


4,040 


6,050 


11,700 


18,600 


32,800 


67,000 


90 


502 


1,010 


1,850 


3,810 


5,700 


11,000 


17,500 


30,900 


63,100 


100 


462 


934 


1,710 


3,510 


5,260 


10,100 


16,100 


28,500 


58,200 


125 


414 


836 


1,530 


3,140 


4,700 


9,060 


14,400 


25,500 


52,100 


150 


372 


751 


1,370 


2,820 


4,220 


8,130 


13,000 


22,900 


46,700 


175 


344 


695 


1,270 


2,601 


3,910 


7,530 


12,000 


21,200 


43,300 


200 


318 


642 


1,170 


2,410 


3,610 


6,960 


11,100 


19,600 


40,000 


250 


279 


583 


1,040 


2,140 


3,210 


6,180 


9,850 


17,400 


35,500 


300 


253 


528 


945 


1,940 


2,910 


5,600 


8,920 


15,800 


32,200 


350 


232 


486 


869 


1,790 


2,670 


5,150 


8,210 


14,500 


29,600 


400 


216 


452 


809 


1,660 


2,490 


4,790 


7,640 


13,500 


27,500 


450 


203 


424 


759 


1,560 


2,330 


4,500 


7,170 


12,700 


25,800 


500 


192 


401 


717 


1,470 


2,210 


4,250 


6,770 


12,000 


24,400 


550 


182 


381 


681 


1,400 


2,090 


4,030 


6,430 


11,400 


23,200 


600 


174 


363 


650 


1,330 


2,000 


3,850 


6,130 


10,800 


22,100 


650 


166 


348 


622 


1,280 


1,910 


3,680 


5,870 


10,400 


21,200 


700 


160 


334 


598 


1,230 


1,840 


3,540 


5,640 


9,970 


20,300 


750 


154 


322 


576 


1,180 


1,770 


3,410 


5,440 


9,610 


19,600 


800 


149 


311 


556 


1,140 


1,710 


3,290 


5,250 


9,280 


18,900 


850 


144 


301 


538 


1,100 


1,650 


3,190 


5,080 


8,980 


18,300 


900 


139 


292 


522 


1,070 


1,600 


3,090 


4,930 


8,710 


17,800 


950 


135 


283 


507 


1,040 


1,560 


3,000 


4,780 


8,460 


17,200 


1,000 


132 


275 


493 


1,010 


1,520 


2,920 


4,650 


8,220 


16,800 


1,100 


125 


262 


468 


960 


1,440 


2,770 


4,420 


7,810 


15,900 


1,200 


119 


250 


446 


917 


1,370 


2,640 


4,220 


7,450 


15,200 


1,300 


114 


239 


427 


878 


1,320 


2,530 


4,040 


7,140 


14,600 


1,400 


110 


230 


411 


843 


1,260 


2,430 


3,880 


6,860 


14,000 


1,500 


106 


221 


396 


812 


1,220 


2,340 


3,740 


6,600 


13,500 


1,600 


102 


214 


382 


784 


1,180 


2,260 


3,610 


6,380 


13,000 


1,700 


99 


207 


370 


759 


1,140 


2,190 


3,490 


6,170 


12,600 


1,800 


96 


200 


358 


736 


1,100 


2,120 


3,390 


5,980 


12,200 


1,900 


93 


195 


348 


715 


1,070 


2,060 


3,290 


5,810 


11,900 


2,000 


91 


189 


339 


695 


1,040 


2,010 


3,200 


5,650 


11,500 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-26 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-26 



Table 6.2(d) Schedule 40 Metallic Pipe 















Gas: 


Natural 




Inlet Pressure: 


3.0 psi 




Pressure Drop: 


2.0 psi 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal: 


Vi 


Vt 


1 


Wi 


l'/a 


2 


VA 


3 


4 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in 


Cubic Feet of Gas per Hour 








10 


2,350 


4,920 


9,270 


19,000 


28,500 


54,900 


87,500 


155,000 


316,000 


20 


1,620 


3,380 


6,370 


13,100 


19,600 


37,700 


60,100 


106,000 


217,000 


30 


1,300 


2,720 


5,110 


10,500 


15,700 


30,300 


48,300 


85,400 


174,000 


40 


1,110 


2,320 


4,380 


8,990 


13,500 


25,900 


41,300 


73,100 


149,000 


50 


985 


2,060 


3,880 


7,970 


11,900 


23,000 


36,600 


64,800 


132,000 


60 


892 


1,870 


3,520 


7,220 


10,800 


20,800 


33,200 


58,700 


120,000 


70 


821 


1,720 


3,230 


6,640 


9,950 


19,200 


30,500 


54,000 


110,000 


80 


764 


1,600 


3,010 


6,180 


9,260 


17,800 


28,400 


50,200 


102,000 


90 


717 


1,500 


2,820 


5,800 


8,680 


16,700 


26,700 


47,100 


96,100 


100 


677 


1,420 


2,670 


5,470 


8,200 


15,800 


25,200 


44,500 


90,800 


125 


600 


1,250 


2,360 


4,850 


7,270 


14,000 


22,300 


39,500 


80,500 


150 


544 


1,140 


2,140 


4,400 


6,590 


12,700 


20,200 


35,700 


72,900 


175 


500 


1,050 


1,970 


4,040 


6,060 


11,700 


18,600 


32,900 


67,100 


200 


465 


973 


1,830 


3,760 


5,640 


10,900 


17,300 


30,600 


62,400 


250 


412 


862 


1,620 


3,330 


5,000 


9,620 


15,300 


27,100 


55,300 


300 


374 


781 


1,470 


3,020 


4,530 


8,720 


13,900 


24,600 


50,100 


350 


344 


719 


1,350 


2,780 


4,170 


8,020 


12,800 


22,600 


46,100 


400 


320 


669 


1,260 


2,590 


3,870 


7,460 


11,900 


21,000 


42,900 


450 


300 


627 


1,180 


2,430 


3,640 


7,000 


11,200 


19,700 


40,200 


500 


283 


593 


1,120 


2,290 


3,430 


6,610 


10,500 


18,600 


38,000 


550 


269 


563 


1,060 


2,180 


3,260 


6,280 


10,000 


17,700 


36,100 


600 


257 


537 


1,010 


2,080 


3,110 


5,990 


9,550 


16,900 


34,400 


650 


246 


514 


' 969 


1,990 


2,980 


5,740 


9,150 


16,200 


33,000 


700 


236 


494 


931 


1,910 


2,860 


5,510 


8,790 


15,500 


31,700 


750 


228 


476 


897 


1,840 


2,760 


5,310 


8,470 


15,000 


30,500 


800 


220 


460 


866 


1,780 


2,660 


5,130 


8,180 


14,500 


29,500 


850 


213 


445 


838 


1,720 


2,580 


4,960 


7,910 


14,000 


28,500 


900 


206 


431 


812 


1,670 


2,500 


4,810 


7,670 


13,600 


27,700 


950 


200 


419 


789 


1,620 


2,430 


4,670 


7,450 


13,200 


26,900 


1,000 


195 


407 


767 


1,580 


2,360 


4,550 


7,240 


12,800 


26,100 


1,100 


185 


387 


729 


1,500 


2,240 


4,320 


6,890 


12,200 


24,800 


1,200 


177 


369 


695 


1,430 


2,140 


4,120 


6,570 


11,600 


23,700 


1,300 


169 


353 


666 


1,370 


2,050 


3,940 


6,290 


11,100 


22,700 


1,400 


162 


340 


640 


1,310 


1,970 


3,790 


6,040 


10,700 


21,800 


1,500 


156 


327 


616 


1,270 


1,900 


3,650 


5,820 


10,300 


21,000 


1,600 


151 


316 


595 


1,220 


1,830 


3,530 


5,620 


10,000 


20,300 


1,700 


146 


306 


576 


1,180 


1,770 


3,410 


5,440 


9,610 


19,600 


1,800 


142 


296 


558 


1,150 


1,720 


3,310 


5,270 


9,320 


19,000 


1,900 


138 


288 


542 


1,110 


1,670 


3,210 


5,120 


9,050 


18,400 


2,000 


134 


280 


527 


1,080 


1,620 


3,120 


4,980 


8,800 


18,000 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223. 1-27 



PIPE SIZING 



54-27 



Table 6.2(e) Schedule 40 Metallic Pipe 















Gas: 


Natural 




Inlet Pressure: 


5.0 psi 




Pressure Drop: 


3.5 psi 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal: 


V, 


3 /4 


1 


11/4 


1V4 


2 


Vh 


3 


4 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in 


Cubic Feet of Gas per Hour 








10 


3,190 


6,430 


11,800 


24,200 


36,200 


69,700 


111,000 


196,000 


401,000 


20 


2,250 


4,550 


8,320 


17,100 


25,600 


49,300 


78,600 


139,000 


283,000 


30 


1,840 


3,720 


6,790 


14,000 


20,900 


40,300 


64,200 


113,000 


231,000 


40 


1,590 


3,220 


5,880 


12,100 


18,100 


34,900 


55,600 


98,200 


200,000 


50 


1,430 


2,880 


5,260 


10,800 


16,200 


31,200 


49,700 


87,900 


179,000 


60 


1,300 


2,630 


4,800 


9,860 


14,800 


28,500 


45,400 


80,200 


164,000 


70 


1,200 


2,430 


4,450 


9,130 


13,700 


26,400 


42,000 


74,300 


151,000 


80 


1,150 


2,330 


4,260 


8,540 


12,800 


24,700 


39,300 


69,500 


142,000 


90 


1,060 


2,150 


3,920 


8,050 


12,100 


23,200 


37,000 


65,500 


134,000 


100 


979 


1,980 


3,620 


7,430 


11,100 


21,400 


34,200 


60,400 


123,000 


125 


876 


1,770 


3,240 


6,640 


9,950 


19,200 


30,600 


54,000 


110,000 


150 


786 


1,590 


2,910 


5,960 


8,940 


17,200 


27,400 


48,500 


98,900 


175 


728 


1,470 


2,690 


5,520 


8,270 


15,900 


25,400 


44,900 


91,600 


200 


673 


1,360 


2,490 


5,100 


7,650 


14,700 


23,500 


41,500 


84,700 


250 


558 


1,170 


2,200 


4,510 


6,760 


13,000 


20,800 


36,700 


74,900 


300 


506 


1,060 


1,990 


4,090 


6,130 


11,800 


18,800 


33,300 


67,800 


350 


465 


973 


1,830 


3,760 


5,640 


10,900 


17,300 


30,600 


62,400 


400 


433 


905 


1,710 


3,500 


5,250 


10,100 


16,100 


28,500 


58,100 


450 


406 


849 


1,600 


3,290 


4,920 


9,480 


15,100 


26,700 


54,500 


500 


384 


802 


1,510 


3,100 


4,650 


8,950 


14,300 


25,200 


51,500 


550 


364 


762 


1,440 


2,950 


4,420 


8,500 


13,600 


24,000 


48,900 


600 


348 


727 


1,370 


2,810 


4,210 


8,110 


12,900 


22,900 


46,600 


650 


333 


696 


1,310 


2,690 


4,030 


7,770 


12,400 


21,900 


44,600 


700 


320 


669 


1,260 


2,590 


3,880 


7,460 


11,900 


21,000 


42,900 


750 


308 


644 


1,210 


2,490 


3,730 


7,190 


11,500 


20,300 


41,300 


800 


298 


622 


1,170 


2,410 


3,610 


6,940 


11,100 


19,600 


39,900 


850 


288 


602 


1,130 


2,330 


3,490 


6,720 


10,700 


18,900 


38,600 


900 


279 


584 


1,100 


2,260 


3,380 


6,520 


10,400 


18,400 


37,400 


950 


271 


567 


1,070 


2,190 


3,290 


6,330 


10,100 


17,800 


36,400 


1,000 


264 


551 


1,040 


2,130 


3,200 


6,150 


9,810 


17,300 


35,400 


1,100 


250 


524 


987 


2,030 


3,030 


5,840 


9,320 


16,500 


33,600 


1,200 


239 


500 


941 


1,930 


2,900 


5,580 


8,890 


15,700 


32,000 


1,300 


229 


478 


901 


1,850 


2,770 


5,340 


8,510 


15,000 


30,700 


1,400 


220 


460 


866 


1,780 


2,660 


5,130 


8,180 


14,500 


29,500 


1,500 


212 


443 


834 


1,710 


2,570 


4,940 


7,880 


13,900 


28,400 


1,600 


205 


428 


806 


1,650 


2,480 


4,770 


7,610 


13,400 


27,400 


1,700 


198 


414 


780 


1,600 


2,400 


4,620 


7,360 


13,000 


26,500 


1,800 


192 


401 


756 


1,550 


2,330 


4,480 


7,140 


12,600 


25,700 


1,900 


186 


390 


734 


1,510 


2,260 


4,350 


6,930 


12,300 


25,000 


2,000 


181 


379 


714 


1,470 


2,200 


4,230 


6,740 


11,900 


24,300 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-28 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-28 



Table 6.2(f) Semi-Rigid Copper Tubing 



















Gas: 


Natural 




Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.3 in. w.c. 




Specific Gravity: 


0.60 




Tube Size (in.) 




K&L: 


'A 


% 


'A 


% 


% 


1 


1V4 


l'/2 


2 


Nominal: 
























ACR: 


% 


»/2 


■ % 


% 


% 


Wa 


lVs 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


20 


42 


85 


148 


210 


448 


806 


1,270 


2,650 


20 


14 


29 


58 


102 


144 


308 


554 


873 


1,820 


30 


11 


23 


47 


82 


116 


247 


445 


701 


1,460 


40 


10 


20 


40 


70 


99 


211 


381 


600 


1,250 


50 


NA 


17 


35 


62 


88 


187 


337 


532 


1,110 


60 


NA 


16 


32 


56 


79 


170 


306 


482 


1,000 


70 


NA 


14 


29 


52 


73 


156 


281 


443 


924 


80 


NA 


13 


27 


48 


68 


145 


262 


413 


859 


90 


NA 


13 


26 


45 


64 


136 


245 


387 


806 


100 


NA 


12 


24 


43 


60 


129 


232 


366 


761 


125 


NA 


11 


22 


38 


53 


114 


206 


324 


675 


150 


NA 


10 


20 


34 


48 


103 


186 


294 


612 


175 


NA 


NA 


18 


31 


45 


95 


171 


270 


563 


200 


NA 


NA 


17 


29 


41 


89 


159 


251 


523 


250 


NA 


NA 


15 


26 


37 


78 


141 


223 


464 


300 


NA 


NA 


13 


23 


33 


71 


128 


202 


420 


350 


NA 


NA 


12 


22 


31 


65 


118 


186 


387 


400 


NA 


NA 


11 


20 


28 


61 


110 


173 


360 


450 


NA 


NA 


11 


19 


27 


57 


103 


162 


338 


500 


NA 


NA 


10 


18 


25 


54 


97 


153 


319 


550 


NA 


NA 


NA 


17 


24 


51 


92 


145 


303 


600 


NA 


NA 


NA 


16 


23 


49 


88 


139 


289 


650 


NA 


NA 


NA 


15 


22 


47 


84 


133 


277 


700 


NA 


NA 


NA 


15 


21 


45 


81 


128 


266 


750 


NA 


NA 


NA 


14 


20 


43 


78 


123 


256 


800 


NA 


NA 


NA 


14 


20 


42 


75 


119 


247 


850 


NA 


NA 


NA 


13 


19 


40 


73 


115 


239 


900 


NA 


NA 


NA 


13 


18 


39 


71 


111 


232 


950 


NA 


NA 


NA 


13 


18 


38 


69 


108 


225 


1,000 


NA 


NA 


NA 


12 


17 


37 


67 


105 


219 


1,100 


NA 


NA 


NA 


12 


16 


35 


63 


100 


208 


1,200 


NA 


NA 


NA 


11 


16 


34 


60 


95 


199 


1,300 


NA 


NA 


NA 


11 


15 


32 


58 


91 


190 


1,400 


NA 


NA 


NA 


10 


14 


31 


56 


88 


183 


1,500 


NA 


NA 


NA 


NA 


14 


30 


54 


84 


176 


1,600 


NA 


NA 


NA 


NA 


13 


29 


52 


82 


170 


1,700 


NA 


NA 


NA 


NA 


13 


28 


50 


79 


164 


1,800 


NA 


NA 


NA 


NA 


13 


27 


49 


77 


159 


1,900 


NA 


NA 


NA 


NA 


12 


26 


47 


74 


155 


2,000 


NA 


NA 


NA 


NA 


12 


25 


46 


72 


151 



NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 

"Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223. 1-29 



PIPE SIZING 



54-29 



Table 6.2(g) Semi-Rigid Copper Tubing 

















Gas: 


Natural 




Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


0.60 




Tube Size (in.) 


Nominal: 


K&L: 


V* 


% 


v 2 


% 


V4 


1 


VA 


1V4 


2 
























ACR: 


% 


Vi 


% 


% 


Vs 


l'/8 


l 3 / 8 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 








Capacity in 


Cubic Feet of Gas per Hour 








10 


27 


55 


111 


195 


276 


590 


1,060 


1,680 


3,490 


20 


18 


38 


77 


134 


190 


406 


730 


1,150 


2,400 


30 


15 


30 


61 


107 


152 


326 


586 


925 


1,930 


40 


13 


26 


53 


92 


131 


279 


502 


791 


1,650 


50 


11 


23 


47 


82 


116 


247 


445 


701 


1,460 


60 


10 


21 


42 


74 


105 


224 


403 


635 


1,320 


70 


NA 


19 


39 


68 


96 


206 


371 


585 


1,220 


80 


NA 


18 


36 


63 


90 


192 


345 


544 


1,130 


90 


NA 


17 


34 


59 


84 


180 


324 


510 


1,060 


100 


NA 


16 


32 


56 


79 


170 


306 


482 


1,000 


125 


NA 


14 


28 


50 


70 


151 


271 


427 


890 


150 


NA 


13 


26 


45 


64 


136 


245 


387 


806 


175 


NA 


12 


24 


41 


59 


125 


226 


356 


742 


200 


NA 


11 


22 


39 


55 


117 


210 


331 


690 


250 


NA 


NA 


20 


34 


48 


103 


186 


294 


612 


300 


NA 


NA 


18 


31 


44 


94 


169 


266 


554 


350 


NA 


NA 


16 


28 


40 


86 


155 


245 


510 


400 


NA 


NA 


15 


26 


38 


80 


144 


228 


474 


450 


NA 


NA 


14 


25 


35 


75 


135 


214 


445 


500 


NA 


NA 


13 


23 


33 


71 


128 


202 


420 


550 


NA 


NA 


13 


22 


32 


68 


122 


192 


399 


600 


NA 


NA 


12 


21 


30 


64 


116 


183 


381 


650 


NA 


NA 


12 


20 


29 


62 


111 


175 


365 


700 


NA 


NA 


11 


20 


28 


59 


107 


168 


350 


750 


NA 


NA 


11 


19 


27 


57 


103 


162 


338 


800 


NA 


NA 


10 


18 


26 


55 


99 


156 


326 


850 


NA 


NA 


10 


18 


25 


53 


96 


151 


315 


900 


NA 


NA 


NA 


17 


24 


52 


93 


147 


306 


950 


NA 


NA 


NA 


17 


24 


50 


90 


143 


297 


1,000 


NA 


NA 


NA 


16 


23 


49 


88 


139 


289 


1,100 


NA 


NA 


NA 


15 


22 


46 


84 


132 


274 


1,200 


NA 


NA 


NA 


15 


21 


44 


80 


126 


262 


1,300 


NA 


NA 


NA 


14 


20 


42 


76 


120 


251 


1,400 


NA 


NA 


NA 


13 


19 


41 


73 


116 


241 


1,500 


NA 


NA 


NA 


13 


18 


39 


71 


111 


232 


1,600 


NA 


NA 


NA 


13 


18 


38 


68 


108 


224 


1,700 


NA 


NA 


NA 


12 


17 


37 


66 


104 


217 


1,800 


NA 


NA 


NA 


12 


17 


36 


64 


101 


210 


1,900 


NA 


NA 


NA 


11 


16 


35 


62 


98 


204 


2,000 


NA 


NA 


NA 


11 


16 


34 


60 


95 


199 



NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 

"Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



54-30 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-30 



Table 6.2(h) Semi-Rigid Copper Tubing 



Gas: 



Inlet Pressure: 



Pressure Drop: 



Specific Gravity: 



Natural 



Less than 2 psi 



1.0 in. w.c. 



0.60 



SPECIAL USE: .."lube Sizing Between House Line Regulator and the Appliance; H 



Tube Size (in.) 



Nominal: 


K&L: 


Vt 


% 


V* 


5 /8 


% 


1 


l'/4 


l'/2 


2 
























ACR: 


S /8 


'/a 


5 /s 


3 /4 


% 


l'/s 


l'/s 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


39 


80 


162 


283 


402 


859 


1,550 


2,440 


5,080 


20 


27 


55 


111 


195 


276 


590 


1,060 


1,680 


3,490 


30 


21 


44 


89 


156 


222 


474 


853 


1,350 


2,800 


40 


18 


38 


77 


134 


190 


406 


730 


1,150 


2,400 


50 


16 


33 


68 


119 


168 


359 


647 


1,020 


2,130 


60 


15 


30 


61 


107 


152 


326 


586 


925 


1,930 


70 


13 


28 


57 


99 


140 


300 


539 


851 


1,770 


80 


13 


26 


53 


92 


131 


279 


502 


791 


1,650 


90 


12 


24 


49 


86 


122 


262 


471 


742 


1,550 


100 


11 


23 


47 


82 


116 


247 


445 


701 


1,460 


125 


NA 


20 


41 


72 


103 


219 


394 


622 


1,290 


150 


NA 


18 


37 


65 


93 


198 


357 


563 


1,170 


175 


NA 


17 


34 


60 


85 


183 


329 


518 


1,080 


200 


NA 


16 


32 


56 


79 


170 


306 


482 


1,000 


250 


NA 


14 


28 


50 


70 


151 


271 


427 


890 


300 


NA 


13 


26 


45 


64 


136 


245 


387 


806 


350 


NA 


12 


24 


41 


59 


125 


226 


356 


742 


400 


NA 


11 


22 


39 


55 


117 


210 


331 


690 


450 


NA 


10 


21 


36 


51 


110 


197 


311 


647 


500 


NA 


NA 


20 


34 


48 


103 


186 


294 


612 


550 


NA 


NA 


19 


32 


46 


98 


177 


279 


581 


600 


NA 


NA 


18 


31 


44 


94 


169 


266 


554 


650 


NA 


NA 


17 


30 


42 


90 


162 


255 


531 


700 


NA 


NA 


16 


28 


40 


86 


155 


245 


510 


750 


NA 


NA 


16 


27 


39 


83 


150 


236 


491 


800 


NA 


NA 


15 


26 


38 


80 


144 


228 


474 


850 


NA 


NA 


15 


26 


36 


78 


140 


220 


459 


900 


NA 


NA 


14 


25 


35 


75 


135 


214 


445 


950 


NA 


NA 


14 


24 


34 


73 


132 


207 


432 


1,000 


NA 


NA 


13 


23 


33 


71 


128 


202 


420 


1,100 


NA 


NA 


13 


22 


32 


68 


122 


192 


399 


1,200 


NA 


NA 


12 


21 


30 


64 


116 


183 


381 


1,300 


NA 


NA 


12 


20 


29 


62 


111 


175 


365 


1,400 


NA 


NA 


11 


20 


28 


59 


107 


168 


350 


1,500 


NA 


NA 


11 


19 


27 


57 


103 


162 


338 


1,600 


NA 


NA 


10 


18 


26 


55 


99 


156 


326 


1,700 


NA 


NA 


10 


18 


25 


53 


96 


151 


315 


1,800 


NA 


NA 


NA 


17 


24 


52 


93 


147 


306 


1,900 


NA 


NA 


NA 


17 


24 


50 


90 


143 


297 


2,000 


NA 


NA 


NA 


16 


23 


49 


88 


139 


289 



NA means a flow of less than 10 cfh. 

Note; All table entries are rounded to 3 significant digits. 

"Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223.1-31 



PIPE SIZING 



54-31 



Table 6.2(i) Semi-Rigid Copper Tubing 

















Gas: 


Natural 




Inlet Pressure: 


Less than 2.0 


>si 




Pressure Drop: 


17.0 in. w.c. 




Specific Gravity: 


0.60 




Tube Size (in.) 




K&L: 


Vt 


% 


'/2 


5 /s 


% 


1 


VA 


1'/. 


2 


























ACR: 


Vs 


<A 


Vs 


Vt 


% 


l'/s 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


190 


391 


796 


1,390 


1,970 


4,220 


7,590 


12,000 


24,900 


20 


130 


269 


547 


956 


1,360 


2,900 


5,220 


8,230 


17,100 


30 


105 


216 


439 


768 


1,090 


2,330 


4,190 


6,610 


13,800 


40 


90 


185 


376 


657 


932 


1,990 


3,590 


5,650 


11,800 


50 


79 


164 


333 


582 


826 


1,770 


3,180 


5,010 


10,400 


60 


72 


148 


302 


528 


749 


1,600 


2,880 


4,540 


9,460 


70 


66 


137 


278 


486 


689 


1,470 


2,650 


4,180 


8,700 


80 


62 


127 


258 


452 


641 


1,370 


2,460 


3,890 


8,090 


90 


58 


119 


243 


424 


601 


1,280 


2,310 


3,650 


7,590 


100 


55 


113 


229 


400 


568 


1,210 


2,180 


3,440 


7,170 


125 


48 


100 


203 


355 


503 


1,080 


1,940 


3,050 


6,360 


150 


44 


90 


184 


321 


456 


974 


1,750 


2,770 


5,760 


175 


40 


83 


169 


296 


420 


896 


1,610 


2,540 


5,300 


200 


38 


77 


157 


275 


390 


834 


1,500 


2,370 


4,930 


250 


33 


69 


140 


244 


346 


739 


1,330 


2,100 


4,370 


300 


30 


62 


126 


221 


313 


670 


1,210 


1,900 


3,960 


350 


28 


57 


116 


203 


288 


616 


1,110 


1,750 


3,640 


400 


26 


53 


108 


189 


268 


573 


1,030 


1,630 


3,390 


450 


24 


50 


102 


177 


252 


538 


968 


1,530 


3,180 


500 


23 


47 


96 


168 


238 


508 


914 


1,440 


3,000 


550 


22 


45 


91 


159 


226 


482 


868 


1,370 


2,850 


600 


21 


43 


87 


152 


215 


460 


829 


1,310 


2,720 


650 


20 


41 


83 


145 


206 


441 


793 


1,250 


2,610 


700 


19 


39 


80 


140 


198 


423 


762 


1,200 


2,500 


750 


18 


38 


77 


135 


191 


408 


734 


1,160 


2,410 


800 


18 


37 


74 


130 


184 


394 


709 


1,120 


2,330 


850 


17 


35 


72 


126 


178 


381 


686 


1,080 


2,250 


900 


17 


34 


70 


122 


173 


370 


665 


1,050 


2,180 


950 


16 


33 


68 


118 


168 


359 


646 


1,020 


2,120 


1,000 


16 


32 


66 


115 


163 


349 


628 


991 


2,060 


1,100 


15 


31 


63 


109 


155 


332 


597 


941 


1,960 


1,200 


14 


29 


60 


104 


148 


316 


569 


898 


1,870 


1,300 


14 


28 


57 


100 


142 


303 


545 


860 


1,790 


1,400 


13 


27 


55 


96 


136 


291 


524 


826 


1,720 


1,500 


13 


26 


53 


93 


131 


280 


505 


796 


1,660 


1,600 


12 


25 


51 


89 


127 


271 


487 


768 


1,600 


1,700 


12 


24 


49 


86 


123 


262 


472 


744 


1,550 


1,800 


11 


24 


48 


84 


119 


254 


457 


721 


1,500 


1,900 


11 


23 


47 


81 


115 


247 


444 


700 


1,460 


2,000 


11 


22 


45 


79 


112 


240 


432 


681 


1,420 



Note: All table entries are rounded to 3 significant digits. 

'Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



54-32 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-32 



Table 6.2(j) Semi-Rigid Copper Tubing 

















Gas: 


Natural 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


0.60 




Tube Size (in.) 




K&L: 


V4 


% 


V4 


5 /s 


Vi 


1 


Wi 


lVa 


2 


Nominal: 
























ACR: 


% 


V4 


Vb 


Va 


Vb 


l'/s 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 








Capacity in 


Cubic Feet of Gas per Hour 








10 


245 


506 


1,030 


1,800 


2,550 


5,450 


9,820 


15,500 


32,200 


20 


169 


348 


708 


1,240 


1,760 


3,750 


6,750 


10,600 


22,200 


30 


135 


279 


568 


993 


1,410 


3,010 


5,420 


8,550 


17,800 


40 


116 


239 


486 


850 


1,210 


2,580 


4,640 


7,310 


15,200 


50 


103 


212 


431 


754 


1,070 


2,280 


4,110 


6,480 


13,500 


60 


93 


192 


391 


683 


969 


2,070 


3,730 


5,870 


12,200 


70 


86 


177 


359 


628 


891 


1,900 


3,430 


5,400 


11,300 


80 


80 


164 


334 


584 


829 


1,770 


3,190 


5,030 


10,500 


90 


75 


154 


314 


548 


778 


1,660 


2,990 


4,720 


9,820 


100 


71 


146 


296 


518 


735 


1,570 


2,830 


4,450 


9,280 


125 


63 


129 


263 


459 


651 


1,390 


2,500 


3,950 


8,220 


150 


57 


117 


238 


416 


590 


1,260 


2,270 


3,580 


7,450 


175 


52 


108 


219 


383 


543 


1,160 


2,090 


3,290 


6,850 


200 


49 


100 


204 


356 


505 


1,080 


1,940 


3,060 


6,380 


250 


43 


89 


181 


315 


448 


956 


1,720 


2,710 


5,650 


300 


39 


80 


164 


286 


406 


866 


1,560 


2,460 


5,120 


350 


36 


74 


150 


263 


373 


797 


1,430 


2,260 


4,710 


400 


33 


69 


140 


245 


347 


741 


1,330 


2,100 


4,380 


450 


31 


65 


131 


230 


326 


696 


1,250 


1,970 


4,110 


500 


30 


61 


124 


217 


308 


657 


1,180 


1,870 


3,880 


550 


28 


58 


118 


206 


292 


624 


1,120 


1,770 


3,690 


600 


27 


55 


112 


196 


279 


595 


1,070 


1,690 


3,520 


650 


26 


53 


108 


188 


267 


570 


1,030 


1,620 


3,370 


700 


25 


51 


103 


181 


256 


548 


986 


1,550 


3,240 


750 


24 


49 


100 


174 


247 


528 


950 


1,500 


3,120 


800 


23 


47 


96 


168 


239 


510 


917 


1,450 


3,010 


850 


22 


46 


93 


163 


231 


493 


888 


1,400 


2,920 


900 


22 


44 


90 


158 


224 


478 


861 


1,360 


2,830 


950 


21 


43 


88 


153 


217 


464 


836 


1,320 


2,740 


1,000 


20 


42 


85 


149 


211 


452 


813 


1,280 


2,670 


1,100 


19 


40 


81 


142 


201 


429 


772 


1,220 


2,540 


1,200 


18 


38 


77 


135 


192 


409 


737 


1,160 


2,420 


1,300 


18 


36 


74 


129 


183 


392 


705 


1,110 


2,320 


1,400 


17 


35 


71 


124 


176 


376 


678 


1,070 


2,230 


1,500 


16 


34 


68 


120 


170 


363 


653 


1,030 


2,140 


1,600 


16 


33 


66 


116 


164 


350 


630 


994 


2,070 


1,700 


15 


31 


64 


112 


159 


339 


610 


962 


2,000 


1,800 


15 


30 


62 


108 


154 


329 


592 


933 


1,940 


1,900 


14 


30 


60 


105 


149 


319 


575 


906 


1,890 


2,000 


14 


29 


59 


102 


145 


310 


559 


881 


1,830 



Note: All table entries are rounded to 3 significant digits. 

'Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223.1-33 



PIPE SIZING 



54-33 



Table 6.2(k) Semi-Rigid Copper Tubing 



Gas: 



Inlet Pressure: 



Pressure Drop: 



Specific Gravity: 



Natural 



2.0 psi 



1.5 psi 



0.60 



p»,...|V : »{- 


J>Pt.",1.4i UaL Vif "v; uit; » -« - 1- « i from' D V «\ <n.U tr t Ho ae I tilt h t,i!« J"wil to-ir" supplied b) r- 




i ;■ .- fit :i- iJ 




Single Hoi-ose Line Relator .S'ot S^*c«sdii!g IIiO Cubic T'f H pf *■ Hour J'* 






| 




Tube Size (in.) 




K&L: 


Vi 


% 


V4 


Vs 


V, 


1 


l'/4 


Wt 


2 


Nominal: 
























ACR: 


Vs 


V% 


% 


% 


Vi 


l'/8 


l 3 /8 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


303 


625 


1,270 


2,220 


3,150 


6,740 


12,100 


19,100 


39,800 


20 


208 


430 


874 


1,530 


2,170 


4,630 


8,330 


13,100 


27,400 


30 


167 


345 


702 


1,230 


1,740 


3,720 


6,690 


10,600 


22,000 


40 


143 


295 


601 


1,050 


1,490 


3,180 


5,730 


9,030 


18,800 


50 


127 


262 


532 


931 


1,320 


2,820 


5,080 


8,000 


16,700 


60 


115 


237 


482 


843 


1,200 


2,560 


4,600 


7,250 


15,100 


70 


106 


218 


444 


776 


1,100 


2,350 


4,230 


6,670 


13,900 


80 


98 


203 


413 


722 


1,020 


2,190 


3,940 


6,210 


12,900 


90 


92 


190 


387 


677 


961 


2,050 


3,690 


5,820 


12,100 


100 


87 


180 


366 


640 


907 


1,940 


3,490 


5,500 


11,500 


125 


77 


159 


324 


567 


804 


1,720 


3,090 


4,880 


10,200 


150 


70 


144 


294 


514 


729 


1,560 


2,800 


4,420 


9,200 


175 


64 


133 


270 


472 


670 


1,430 


2,580 


4,060 


8,460 


200 


60 


124 


252 


440 


624 


1,330 


2,400 


3,780 


7,870 


250 


53 


110 


223 


390 


553 


1,180 


2,130 


3,350 


6,980 


300 


48 


99 


202 


353 


501 


1,070 


1,930 


3,040 


6,320 


350 


44 


91 


186 


325 


461 


984 


1,770 


2,790 


5,820 


400 


41 


85 


173 


302 


429 


916 


1,650 


2,600 


5,410 


450 


39 


80 


162 


283 


402 


859 


1,550 


2,440 


5,080 


500 


36 


75 


153 


268 


380 


811 


1,460 


2,300 


4,800 


550 


35 


72 


146 


254 


361 


771 


1,390 


2,190 


4,560 


600 


33 


68 


139 


243 


344 


735 


1,320 


2,090 


4,350 


650 


32 


65 


133 


232 


330 


704 


1,270 


2,000 


4,160 


700 


30 


63 


128 


223 


317 


676 


1,220 


1,920 


4,000 


750 


29 


60 


123 


215 


305 


652 


1,170 


1,850 


3,850 


800 


28 


58 


119 


208 


295 


629 


1,130 


1,790 


3,720 


850 


27 


57 


115 


201 


285 


609 


1,100 


1,730 


3,600 


900 


27 


55 


111 


195 


276 


590 


1,060 


1,680 


3,490 


950 


26 


53 


108 


189 


268 


573 


1,030 


1,630 


3,390 


, 1,000 


25 


52 


105 


184 


261 


558 


1,000 


1,580 


3,300 


1,100 


24 


49 


100 


175 


248 


530 


954 


1,500 


3,130 


1,200 


23 


47 


95 


167 


237 


505 


910 


1,430 


2,990 


1,300 


22 


45 


91 


160 


227 


484 


871 


1,370 


2,860 


1,400 


21 


43 


88 


153 


218 


465 


837 


1,320 


2,750 


1,500 


20 


42 


85 


148 


210 


448 


806 


1,270 


2,650 


1,600 


19 


40 


82 


143 


202 


432 


779 


1,230 


2,560 


1,700 


19 


39 


79 


138 


196 


419 


753 


1,190 


2,470 


1,800 


18 


38 


77 


134 


190 


406 


731 


1,150 


2,400 


1,900 


18 


37 


74 


130 


184 


394 


709 


1,120 


2,330 


2,000 


17 


36 


72 


126 


179 


383 


690 


1,090 


2,270 



Note: All table entries are rounded to 3 significant digits. 

"Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 
diameter of the copper tubing products. 

t When this table is used to size the tubing upstream of a line pressure regulator, the pipe or tubing down- 
stream of the line pressure regulator shall be sized using a pressure drop no greater than 1 in. w.c. 



2006 Edition 



54-34 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-34 



Table 6.2(1) Semi-Rigid Copper Tubing 

















Gas: 


Natural 




Inlet Pressure: 


5.0 psi 




Pressure Drop: 


3.5 psi 




Specific Gravity: 


0.60 




Tube Size (in.) 




K&L: 


V4 


% 


l A 


5 /8 


3 /4 


1 


VA 


VA 


2 


























ACR: 


% 


'/> 


% 


% 


Va 


lVi 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


511 


1,050 


2,140 


3,750 


5,320 


11,400 


20,400 


32,200 


67,100 


20 


351 


724 


1,470 


2,580 


3,650 


7,800 


14,000 


22,200 


46,100 


30 


282 


582 


1,180 


2,070 


2,930 


6,270 


11,300 


17,800 


37,000 


40 


241 


498 


1,010 


1,770 


2,510 


5,360 


9,660 


15,200 


31,700 


50 


214 


441 


898 


1,570 


2,230 


4,750 


8,560 


13,500 


28,100 


60 


194 


400 


813 


1,420 


2,020 


4,310 


7,750 


12,200 


25,500 


70 


178 


368 


748 


1,310 


1,860 


3,960 


7,130 


11,200 


23,400 


80 


166 


342 


696 


1,220 


1,730 


3,690 


6,640 


10,500 


21,800 


90 


156 


321 


653 


1,140 


1,620 


3,460 


6,230 


9,820 


20,400 


100 


147 


303 


617 


1,080 


1,530 


3,270 


5,880 


9,270 


19,300 


125 


130 


269 


547 


955 


1,360 


2,900 


5,210 


8,220 


17,100 


150 


118 


243 


495 


866 


1,230 


2,620 


4,720 


7,450 


15,500 


175 


109 


224 


456 


796 


1,130 


2,410 


4,350 


6,850 


14,300 


200 


101 


208 


424 


741 


1,050 


2,250 


4,040 


6,370 


13,300 


250 


90 


185 


376 


657 


932 


1,990 


3,580 


5,650 


11,800 


300 


81 


167 


340 


595 


844 


1,800 


3,250 


5,120 


10,700 


350 


75 


154 


313 


547 


777 


1,660 


2,990 


4,710 


9,810 


400 


69 


143 


291 


509 


722 


1,540 


2,780 


4,380 


9,120 


450 


65 


134 


273 


478 


678 


1,450 


2,610 


4,110 


8,560 


500 


62 


127 


258 


451 


640 


1,370 


2,460 


3,880 


8,090 


550 


58 


121 


245 


429 


608 


1,300 


2,340 


3,690 


7,680 


600 


56 


115 


234 


409 


580 


1,240 


2,230 


3,520 


7,330 


650 


53 


110 


224 


392 


556 


1,190 


2,140 


3,370 


7,020 


700 


51 


106 


215 


376 


534 


1,140 


2,050 


3,240 


6,740 


750 


49 


102 


207 


362 


514 


1,100 


1,980 


3,120 


6,490 


800 


48 


98 


200 


350 


497 


1,060 


1,910 


3,010 


6,270 


850 


46 


95 


194 


339 


481 


1,030 


1,850 


2,910 


6,070 


900 


45 


92 


188 


328 


466 


1,000 


1,790 


2,820 


5,880 


950 


43 


90 


182 


319 


452 


967 


1,740 


2,740 


5,710 


1,000 


42 


87 


177 


310 


440 


940 


1,690 


2,670 


5,560 


1,100 


40 


83 


169 


295 


418 


893 


1,610 


2,530 


5,280 


1,200 


38 


79 


161 


281 


399 


852 


1,530 


2,420 


5,040 


1,300 


37 


76 


154 


269 


382 


816 


1,470 


2,320 


4,820 


1,400 


35 


73 


148 


259 


367 


784 


1,410 


2,220 


4,630 


1,500 


34 


70 


143 


249 


353 


755 


1,360 


2,140 


4,460 


1,600 


33 


68 


138 


241 


341 


729 


1,310 


2,070 


4,310 


1,700 


32 


65 


133 


233 


330 


705 


1,270 


2,000 


4,170 


1,800 


31 


63 


129 


226 


320 


684 


1,230 


1,940 


4,040 


1,900 


30 


62 


125 


219 


311 


664 


1,200 


1,890 


3,930 


2,000 


29 


60 


122 


213 


302 


646 


1,160 


1,830 


3,820 



Note: All table entries are rounded to 3 significant digits. 

'Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223. 1-35 



PIPE SIZING 



54-35 



Table 6.2(m) Corrugated Stainless Steel Tubing (CSST) 























Gas: 


Natural 






Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.5 in, w.c. 




Specific Gravity: 


0.60 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


5 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


2,070 


3,660 


4,140 


10 


32 


44 


82 


95 


161 


192 


330 


383 


639 


1,260 


1,470 


2,600 


2,930 


15 


25 


35 


66 


77 


132 


157 


267 


310 


524 


1,030 


1,200 


2,140 


2,400 


20 


22 


31 


58 


67 


116 


137 


231 


269 


456 


888 


1,050 


1,850 


2,080 


25 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


936 


1,660 


1,860 


30 


18 


25 


47 


55 


96 


112 


188 


218 


374 


723 


856 


1,520 


1,700 


40 


15 


21 


41 


47 


83 


97 


162 


188 


325 


625 


742 


1,320 


1,470 


50 


13 


19 


37 


42 


75 


87 


144 


168 


292 


559 


665 


1,180 


1,320 


60 


12 


17 


34 


38 


68 


80 


131 


153 


267 


509 


608 


1,080 


1,200 


70 


11 


16 


31 


36 


63 


74 


121 


141 


248 


471 


563 


1,000 


1,110 


80 


10 


15 


29 


33 


60 


69 


113 


132 


232 


440 


527 


940 


1,040 


90 


10 


14 


28 


32 


57 


65 


107 


125 


219 


415 


498 


887 


983 


100 


9 


13 


26 


30 


54 


62 


101 


118 


208 


393 


472 


843 


933 


150 


7 


10 


20 


23 


42 


48 


78 


91 


171 


320 


387 


691 


762 


200 


6 


9 


18 


21 


38 


44 


71 


82 


148 


277 


336 


600 


661 


250 


5 


8 


16 


19 


34 


39 


63 


74 


133 


247 


301 


538 


591 


300 


5 


7 


15 


17 


32 


36 


57 


67 


95 


226 


275 


492 


540 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table includes losses for four 90 degree bends and two end fittings. Tubing runs with larger numbers of 
bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L= 1.3n, 
where L is additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

(2) All table entries are rounded to 3 significant digits. 



2006 Edition 



54-36 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-36 



Table 6.2(n) Corrugated Stainless Steel Tubing (CSST) 























Gas: 


Natural 






Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


3.0 in. w.c. 




Specific Gravity: 


0.60 




Tube Size (EHD)* 


flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


5 


120 


160 


277 


327 


529 


649 


1,180 


1,370 


2,140 


4,430 


5,010 


8,800 


10,100 


10 


83 


112 


197 


231 


380 


462 


828 


958 


1,530 


3,200 


3,560 


6,270 


7,160 


15 


67 


90 


161 


189 


313 


379 


673 


778 


1,250 


2,540 


2,910 


5,140 


5,850 


20 


57 


78 


140 


164 


273 


329 


580 


672 


1,090 


2,200 


2,530 


4,460 


5,070 


25 


51 


69 


125 


147 


245 


295 


518 


599 


978 


1,960 


2,270 


4,000 


4,540 


30 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


2,070 


3,660 


4,140 


40 


39 


54 


100 


116 


196 


234 


407 


471 


778 


1,550 


1,800 


3,180 


3,590 


50 


35 


48 


89 


104 


176 


210 


363 


421 


698 


1,380 


1,610 


2,850 


3,210 


60 


32 


44 


82 


95 


161 


192 


330 


383 


639 


1,260 


1,470 


2,600 


2,930 


70 


29 


41 


76 


88 


150 


178 


306 


355 


593 


1,170 


1,360 


2,420 


2,720 


80 


27 


38 


71 


82 


141 


167 


285 


331 


555 


1,090 


1,280 


2,260 


2,540 


90 


26 


36 


67 


77 


133 


157 


268 


311 


524 


1,030 


1,200 


2,140 


2,400 


100 


24 


34 


63 


73 


126 


149 


254 


295 


498 


974 


1,140 


2,030 


2,280 


150 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


936 


1,660 


1,860 


200 


17 


23 


45 


52 


91 


106 


178 


207 


355 


686 


812 


1,440 


1,610 


250 


15 


21 


40 


46 


82 


95 


159 


184 


319 


613 


728 


1,290 


1,440 


300 


13 


19 


37 


42 


75 


87 


144 


168 


234 


559 


665 


1,180 


1,320 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1 ) Table includes losses for four 90 degree bends and two end fittings. Tubing runs with larger numbers of 
bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L= 1.3n, 
where Lis additional length (ft) of tubing and nis the number of additional fittings and/or bends. 

(2) All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-37 



PIPE SIZING 



54-37 



Table 6.2(o) Corrugated Stainless Steel Tubing (CSST) 























Gas: 


Natural 






Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


6.0 in. w.c. 




Specific Gravity: 


0.60 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


5 


173 


229 


389 


461 


737 


911 


1,690 


1,950 


3,000 


6,280 


7,050 


12,400 


14,260 


10 


120 


160 


277 


327 


529 


649 


1,180 


1,370 


2,140 


4,430 


5,010 


8,800 


10,100 


15 


96 


130 


227 


267 


436 


532 


960 


1,110 


1,760 


3,610 


4,100 


7,210 


8,260 


20 


83 


112 


197 


231 


380 


462 


828 


958 


1,530 


3,120 


3,560 


6,270 


7,160 


25 


74 


99 


176 


207 


342 


414 


739 


855 


1,370 


2,790 


3,190 


5,620 


6,400 


30 


67 


90 


161 


189 


313 


379 


673 


778 


1,250 


2,540 


2,910 


5,140 


5,850 


40 


57 


78 


140 


164 


273 


329 


580 


672 


1,090 


2,200 


2,530 


4,460 


5,070 


50 


51 


69 


125 


147 


245 


295 


518 


599 


978 


1,960 


2,270 


4,000 


4,540 


60 


46 


63 


115 


134 


225 


270 


471 


546 


895 


1,790 


2,070 


3,660 


4,140 


70 


42 


58 


106 


124 


209 


250 


435 


505 


830 


1,660 


1,920 


3,390 


3,840 


80 


39 


54 


100 


116 


196 


234 


407 


471 


778 


1,550 


1,800 


3,180 


3,590 


90 


37 


51 


94 


109 


185 


221 


383 


444 


735 


1,460 


1,700 


3,000 


3,390 


100 


35 


48 


89 


104 


176 


210 


363 


421 


698 


1,380 


1,610 


2,850 


3,210 


150 


28 


39 


73 


85 


145 


172 


294 


342 


573 


1,130 


1,320 


2,340 


2,630 


200 


24 


34 


63 


73 


126 


149 


254 


295 


498 


974 


1,140 


2,030 


2,280 


250 


21 


30 


57 


66 


114 


134 


226 


263 


447 


870 


1,020 


1,820 


2,040 


300 


19 


27 


52 


60 


104 


122 


206 


240 


409 


793 


936 


1,660 


1,860 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger numbers of 
bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L= 1.3re, 
where L is additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

(2) All table entries are rounded to 3 significant digits. 



2006 Edition 



54-38 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-38 



Table 6.2 (p) Corrugated Stainless Steel Tubing (CSST) 


























Gas: 


Natural 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 






Specific Gravity: 


0.60 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


270 


353 


587 


700 


1,100 


1,370 


2,590 


2,990 


4,510 


9,600 


10,700 


18,600 


21,600 


25 


166 


220 


374 


444 


709 


876 


1,620 


1,870 


2,890 


6,040 


6,780 


11,900 


13,700 


30 


151 


200 


342 


405 


650 


801 


1,480 


1,700 


2,640 


5,510 


6,200 


10,900 


12,500 


40 


129 


172 


297 


351 


567 


696 


1,270 


1,470 


2,300 


4,760 


5,380 


9,440 


10,900 


50 


115 


154 


266 


314 


510 


624 


1,140 


1,310 


2,060 


4,260 


4,820 


8,470 


9,720 


75 


93 


124 


218 


257 


420 


512 


922 


1,070 


1,690 


3,470 


3,950 


6,940 


7,940 


80 


89 


120 


211 


249 


407 


496 


892 


1,030 


1,640 


3,360 


3,820 


6,730 


7,690 


100 


79 


107 


189 


222 


366 


445 


795 


920 


1,470 


3,000 


3,420 


6,030 


6,880 


150 


64 


87 


155 


182 


302 


364 


646 


748 


1,210 


2,440 


2,800 


4,940 


5,620 


200 


55 


75 


135 


157 


263 


317 


557 


645 


1,050 


2,110 


2,430 


4,290 


4,870 


250 


49 


67 


121 


141 


236 


284 


497 


576 


941 


1,890 


2,180 


3,850 


4,360 


300 


44 


61 


110 


129 


217 


260 


453 


525 


862 


1,720 


1,990 


3,520 


3,980 


400 


38 


52 


96 


111 


189 


225 


390 


453 


749 


1,490 


1,730 


3,060 


3,450 


500 


34 


46 


86 


100 


170 


202 


348 


404 


552 


1,330 


1,550 


2,740 


3,090 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 
% psi, do not usethis table. Consult with regulator manufacturer for pressure drops and capacity factors. 
Pressure drops across a regulator may vary with flow rate. 

(2) CAUTION: Capacities shown in table may exceed maximum capacity for a selected regulator. Consult 
with regulator or tubing manufacturer for guidance. 

(3) Table includes losses for four 90-degree bends and two end fittings. Tubing runs with larger number of 
bends and/ or fittings shall be increased by an equivalent length of tubing according to the following equa- 
tion: L = 1 .3n, where L is additional length (ft) of tubing and n is the number of additional fittings and/or 
bends. 

(4) All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-39 



PIPE SIZING 



54-39 



Table 6.2(q) Corrugated 


Stainless Steel Tubing (CSST) 


























Gas: 


Natural 




Inlet Pressure: 


5.0 psi 




Pressure Drop: 


3.5 psi 






Specific Gravity: 


0.60 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


523 


674 


1,080 


1,300 


2,000 


2,530 


4,920 


5,660 


8,300 


18,100 


19,800 


34,400 


40,400 


25 


322 


420 


691 


827 


1,290 


1,620 


3,080 


3,540 


5,310 


11,400 


12,600 


22,000 


25,600 


30 


292 


382 


632 


755 


1,180 


1,480 


2,800 


3,230 


4,860 


10,400 


11,500 


20,100 


23,400 


40 


251 


329 


549 


654 


1,030 


1,280 


2,420 


2,790 


4,230 


8,970 


10,000 


17,400 


20,200 


50 


223 


293 


492 


586 


926 


1,150 


2,160 


2,490 


3,790 


8,020 


8,930 


15,600 


18,100 


75 


180 


238 


403 


479 


763 


944 


1,750 


2,020 


3,110 


6,530 


7,320 


12,800 


14,800 


80 


174 


230 


391 


463 


740 


915 


1,690 


1,960 


3,020 


6,320 


7,090 


12,400 


14,300 


100 


154 


205 


350 


415 


665 


820 


1,510 


1,740 


2,710 


5,650 


6,350 


11,100 


12,800 


150 


124 


166 


287 


339 


548 


672 


1,230 


1,420 


2,220 


4,600 


5,200 


9,130 


10,500 


200 


107 


143 


249 


294 


478 


584 


1,060 


1,220 


1,930 


3,980 


4,510 


7,930 


9,090 


250 


95 


128 


223 


263 


430 


524 


945 


1,090 


1,730 


3,550 


4,040 


7,110 


8,140 


300 


86 


116 


204 


240 


394 


479 


860 


995 


1,590 


3,240 


3,690 


6,500 


7,430 


400 


74 


100 


177 


208 


343 


416 


742 


858 


1,380 


2,800 


3,210 


5,650 


6,440 


500 


66 


89 


159 


186 


309 


373 


662 


766 


1,040 


2,500 


2,870 


5,060 


5,760 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table does not include effect of pressure drop across line regulator. Where regulator loss exceeds 1 psi, 
do not use this table. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure 
drop across regulator may vary with the flow rate. 

(2) CAUTION: Capacities shown in table may exceed maximum capacity of selected regulator. Consult with 
tubing manufacturer for guidance. 

(3) Table includes losses for four 90-degree bends and two end Fittings. Tubing runs with larger numbers of 
bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L = 1 .3n, 
where L is additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

(4) All table entries are rounded to 3 significant digits. 



2006 Edition 



54-40 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-40 



Table 6.2 (r) Polyethylene Plastic Pipe 









Gas: 


Natural 




Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.3 in. w.c. 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal OD: 


V4 


S A 


1 


l'/4 


1V4 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID: 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length (ft) 




Capacity in Cubic Feet of Gas per How- 


10 


153 


SOS 


551 


955 


1,440 


2,590 


20 


105 


210 


379 


656 


991 


1,780 


30 


84 


169 


304 


527 


796 


1,430 


40 


72 


144 


260 


451 


681 


. 1,220 


50 


64 


128 


231 


400 


604 


1,080 


60 


58 


116 


209 


362 


547 


983 


70 


53 


107 


192 


333 


503 


904 


80 


50 


99 


179 


310 


468 


841 


90 


46 


93 


168 


291 


439 


789 


100 


44 


88 


159 


275 


415 


745 


125 


39 


78 


141 


243 


368 


661 


150 


35 


71 


127 


221 


333 


598 


175 


32 


65 


117 


203 


306 


551 


200 


30 


60 


109 


189 


285 


512 


250 


27 


54 


97 


167 


253 


454 


300 


24 


48 


88 


152 


229 


411 


350 


22 


45 


81 


139 


211 


378 


400 


21 


42 


75 


130 


196 


352 


450 


19 


39 


70 


122 


184 


330 


500 


18 


37 


66 


115 


174 


312 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223. 1-41 



PIPE SIZING 



54-41 



Table 6.2 (s) Polyethylene Plastic Pipe 









Gas: 


Natural 




Inlet Pressure: 


Less than 2 psi 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal OD: 


'/2 


3 /4 


1 


l'/t 


V/i 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID: 


o.eeo 


0.860 


1.077 


1.328 


1.554 


1.943 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


201 


403 


726 


1,260 


1,900 


3,410 


20 


138 


277 


499 


865 


1,310 


2,350 


30 


111 


222 


401 


695 


1,050 


1,880 


40 


95 


190 


343 


594 


898 


1,610 


50 


84 


169 


304 


527 


796 


1,430 


60 


76 


153 


276 


477 


721 


1,300 


70 


70 


140 


254 


439 


663 


1,190 


80 


65 


131 


236 


409 


617 


1,110 


90 


61 


123 


221 


383 


579 


1,040 


100 


58 


116 


209 


362 


547 


983 


125 


51 


103 


185 


321 


485 


871 


150 


46 


93 


168 


291 


439 


789 


175 


43 


86 


154 


268 


404 


726 


200 


40 


80 


144 


249 


376 


675 


250 


35 


71 


127 


221 


333 


598 


300 


32 


64 


115 


200 


302 


542 


350 


29 


59 


106 


184 


278 


499 


400 


27 


55 


99 


171 


258 


464 


450 


26 


51 


93 


160 


242 


435 


500 


24 


48 


88 


152 


229 


411 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-42 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-42 



Table 6.2(t) Polyethylene Plastic Pipe 









Gas: 


Natural 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


0.60 




Pipe Size (in.) 


Nominal OD: 


l A 


% 


1 


VA 


l'/2 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID: 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


1,860 


3,720 


6,710 


11,600 


17,600 


31,600 


20 


1,280 


2,560 


4,610 


7,990 


12,100 


21,700 


30 


1,030 


2,050 


3,710 


6,420 


9,690 


17,400 


40 


878 


1,760 


3,170 


5,490 


8,300 


14,900 


50 


778 


1,560 


2,810 


4,870 


7,350 


13,200 


60 


705 


1,410 


2,550 


4,410 


6,660 


12,000 


70 


649 


1,300 


2,340 


4,060 


6,130 


11,000 


80 


603 


1,210 


2,180 


3,780 


5,700 


10,200 


90 


566 


1,130 


2,050 


3,540 


5,350 


9,610 


100 


535 


1,070 


1,930 


3,350 


5,050 


9,080 


125 


474 


949 


1,710 


2,970 


4,480 


8,050 


150 


429 


860 


1,550 


2,690 


4,060 


7,290 


175 


395 


791 


1,430 


2,470 


3,730 


6,710 


200 


368 


736 


1,330 


2,300 


3,470 


6,240 


250 


326 


652 


1,180 


2,040 


3,080 


5,530 


300 


295 


591 


1,070 


1,850 


2,790 


5,010 


350 


272 


544 


981 


1,700 


2,570 


4,610 


400 


253 


506 


913 


1,580 


2,390 


4,290 


450 


237 


475 


856 


1,480 


2,240 


4,020 


500 


224 


448 


809 


1,400 


2,120 


3,800 


550 


213 


426 


768 


1,330 


2,010 


3,610 


600 


203 


406 


733 


1,270 


1,920 


3,440 


650 


194 


389 


702 


1,220 


1,840 


3,300 


700 


187 


374 


674 


1,170 


1,760 


3,170 


750 


180 


360 


649 


1,130 


1,700 


3,050 


800 


174 


348 


627 


1,090 


1,640 


2,950 


850 


168 


336 


607 


1,050 


1,590 


2,850 


900 


163 


326 


588 


1,020 


1,540 


2,770 


950 


158 


317 


572 


990 


1,500 


2,690 


1,000 


154 


308 


556 


963 


1,450. 


2,610 


1,100 


146 


293 


528 


915 


1,380 


2,480 


1,200 


139 


279 


504 


873 


1,320 


2,370 


1,300 


134 


267 


482 


836 


1,260 


2,270 


1,400 


128 


257 


463 


803 


1,210 


2,180 


1,500 


124 


247 


446 


773 


1,170 


2,100 


1,600 


119 


239 


431 


747 


1,130 


2,030 


1,700 


115 


231 


417 


723 


1,090 


1,960 


1,800 


112 


224 


404 


701 


1,060 


1,900 


1,900 


109 


218 


393 


680 


1,030 


1,850 


2,000 


106 


212 


382 


662 


1,000 


1,800 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-43 



PIPE SIZING 



54-43 



Table 6.2(u) Polyethylene Plastic Tubing 



Nominal OD: 



Designation: 



Actual ID: 



Length (ft) 



10 
20 
30 
40 
50 



60 
70 
80 
90 
100 



125 
150 
175 
200 



225 
250 
275 
300 



350 
400 
450 
500 



Gas: 



Inlet Pressure: 



Pressure Drop: 



Specific Gravity: 0.60 



Natural 



Less than 2.0 psi 



0.3 in. w.c. 



Plastic Tubing Size (CTS)* (in.) 



SDR 7.00 



0.445 



SDR 11.00 



0.927 



Capacity in Cubic Feet of Gas per Hour 



54 
37 
30 
26 
23 



21 
19 
18 
17 
16 



14 
13 
12 
11 



10 

NA 
NA 

NA 



NA 
NA 
NA 
NA 



372 

256 
205 
176 
156 



141 

130 
121 
113 

107 



95 
86 
79 
74 



69 
65 
62 
59 



54 
51 

47 
45 



*CTS = Copper tube size. 

NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 



Table 6.2 (v) Polyethylene Plastic Tubing 





Gas: 


Natural 




Inlet Pressure: 


Less than 2.0 psi 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


0.60 




Plastic Tubing Size (CTS)* (in.) 


Nominal OD: 


V2 


»/4 


Designation: 


SDR 7.00 


SDR 11.00 


Actual ID: 


0.445 


0.927 


Length (ft) 


Capacity in Cubic Feet of Gas per Hour 


10 


72 


490 


20 


49 


337 


30 


39 


271 


40 


34 


232 


50 


30 


205 


60 


27 


186 


70 


25 


171 


80 


23 


159 


90 


22 


149 


100 


21 


141 


125 


18 


125 


150 


17 


113 


175 


15 


104 


200 


14 


97 


225 


13 


91 


250 


12 


86 


275 


11 


82 


300 


11 


78 


350 


10 


72 


400 


NA 


67 


450 


NA 


63 


500 


NA 


59 



*CTS = Copper tube size. 

NA means a flow of less than 10 cfh. 

Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-44 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-44 



Table 6.3(a) Schedule 40 Metallic Pipe 



Gas: 



Inlet Pressure: 



Pressure Drop: 



Specific Gravity: 



Undiluted Propane 



10.0 psi 



1.0 



psi 



1.50 



SPECIAL 1'SE: Pipe Sizing Between First Stage (High Pressure Regulator) and Second Stage (Low Pressure Regulator) 

Pipe Size (in.) 



Nominal 




















Inside: 


V4 


3 /4 


1 


1V4 


IVi 


2 


2>/2 


3 


4 


Actual: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in Thousands of Btu 


per Hour 








10 


3,320 


6,950 


13,100 


26,900 


40,300 


77,600 


124,000 


219,000 


446,000 


20 


2,280 


4,780 


9,000 


18,500 


27,700 


53,300 


85,000 


150,000 


306,000 


SO 


1,830 


3,840 


7,220 


14,800 


22,200 


42,800 


68,200 


121 ,000 


246,000 


40 


1,570 


3,280 


6,180 


12,700 


19,000 


36,600 


58,400 


103,000 


211,000 


50 


1,390 


2,910 


5,480 


11,300 


16,900 


32,500 


51,700 


91,500 


187,000 


60 


1,260 


2,640 


4,970 


10,200 


15,300 


29,400 


46,900 


82,900 


169,000 


70 


1,160 


2,430 


4,570 


9,380 


14,100 


27,100 


43,100 


76,300 


156,000 


80 


1,080 


2,260 


4,250 


8,730 


13,100 


25,200 


40,100 


70,900 


145,000 


90 


1,010 


2,120 


3,990 


8,190 


12,300 


23,600 


37,700 


66,600 


136,000 


100 


956 


2,000 


3,770 


7,730 


11,600 


22,300 


35,600 


62,900 


128,000 


125 


848 


1,770 


3,340 


6,850 


10,300 


19,800 


31,500 


55,700 


114,000 


150 


768 


1,610 


3,020 


6,210 


9,300 


17,900 


28,600 


50,500 


103,000 


175 


706 


1,480 


2,780 


5,710 


8,560 


16,500 


26,300 


46,500 


94,700 


200 


657 


1,370 


2,590 


5,320 


7,960 


15,300 


24,400 


43,200 


88,100 


250 


582 


1,220 


2,290 


4,710 


7,060 


13,600 


21,700 


38,300 


78,100 


300 


528 


1,100 


2,080 


4,270 


6,400 


12,300 


19,600 


34,700 


70,800 


350 


486 


1,020 


1,910 


3,930 


5,880 


11,300 


18,100 


31,900 


65,100 


400 


452 


945 


1,780 


3,650 


5,470 


10,500 


16,800 


29,700 


60,600 


450 


424 


886 


1,670 


3,430 


5,140 


9,890 


15,800 


27,900 


56,800 


500 


400 


837 


1,580 


3,240 


4,850 


9,340 


14,900 


26,300 


53,700 


550 


380 


795 


1,500 


3,070 


4,610 


8,870 


14,100 


25,000 


51,000 


600 


363 


759 


1,430 


2,930 


4,400 


8,460 


13,500 


23,900 


48,600 


650 


347 


726 


1,370 


2,810 


4,210 


8,110 


12,900 


22,800 


46,600 


700 


334 


698 


1,310 


2,700 


4,040 


7,790 


12,400 


21,900 


44,800 


750 


321 


672 


1,270 


2,600 


3,900 


7,500 


12,000 


21,100 


43,100 


800 


310 


649 


1,220 


2,510 


3,760 


7,240 


11,500 


20,400 


41,600 


850 


300 


628 


1,180 


2,430 


3,640 


7,010 


11,200 


19,800 


40,300 


900 


291 


609 


1,150 


2,360 


3,530 


6,800 


10,800 


19,200 


39,100 


950 


283 


592 


1,110 


2,290 


3,430 


6,600 


10,500 


18,600 


37,900 


1,000 


275 


575 


1,080 


2,230 


3,330 


6,420 


10,200 


18,100 


36,900 


1,100 


261 


546 


1,030 


2,110 


3,170 


6,100 


9,720 


17,200 


35,000 


1,200 


249 


521 


982 


2,020 


3,020 


5,820 


9,270 


16,400 


33,400 


1,300 


239 


499 


940 


1,930 


2,890 


5,570 


8,880 


15,700 


32,000 


1,400 


229 


480 


903 


1,850 


2,780 


5,350 


8,530 


15,100 


30,800 


1,500 


221 


462 


870 


1,790 


2,680 


5,160 


8,220 


14,500 


29,600 


1,600 


213 


446 


840 


1,730 


2,590 


4,980 


7,940 


14,000 


28,600 


1,700 


206 


432 


813 


1,670 


2,500 


4,820 


7,680 


13,600 


27,700 


1,800 


200 


419 


789 


1,620 


2,430 


4,670 


7,450 


13,200 


26,900 


1,900 


194 


407 


766 


1,570 


2,360 


4,540 


7,230 


12,800 


26,100 


2,000 


189 


395 


745 


1,530 


2,290 


4,410 


7,030 


12,400 


25,400 



| Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-45 



PIPE SIZING 



54-45 



Table 6.3(b) Schedule 40 Metallic Pipe 





Gas: 


Undiluted Propane 




Inlet Pressure: 


10.0 psi 




Pressure Drop: 


3.0 psi 




Specific Gravity: 


1.50 



Si's «Il*i! USC' !*>(>•■ *M*wp «fc£tw"L] F Jir'tStafc*" (H $I« lftt^wi B*-^tflalur; .Jhrl b?-wmf* M. ge (L^w Pressure Regulator) 

Pipe Size (in.) 



Nominal 




















Inside: 


V4 


Vt 


1 


114 


l'/2 


2 


2'/4 


3 


4 


Actual: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in 


Thousands of Btu per Hour 








10 


5,890 


12,300 


23,200 


47,600 


71,300 


137,000 


219,000 


387,000 


789,000 


20 


4,050 


8,460 


15,900 


32,700 


49,000 


94,400 


150,000 


266,000 


543,000 


30 


3,250 


6,790 


12,800 


26,300 


39,400 


75,800 


121,000 


214,000 


436,000 


40 


2,780 


5,810 


11,000 


22,500 


33,700 


64,900 


103,000 


183,000 


373,000 


50 


2,460 


5,150 


9,710 


19,900 


29,900 


57,500 


91,600 


162,000 


330,000 


60 


2,230 


4,670 


8,790 


18,100 


27,100 


52,100 


83,000 


147,000 


299,000 


70 


2,050 


4,300 


8,090 


16,600 


24,900 


47,900 


76,400 


135,000 


275,000 


80 


1,910 


4,000 


7,530 


15,500 


23,200 


44,600 


71,100 


126,000 


256,000 


90 


1,790 


3,750 


7,060 


14,500 


21,700 


41,800 


66,700 


118,000 


240,000 


100 


1,690 


3,540 


6,670 


13,700 


20,500 


39,500 


63,000 


111,000 


227,000 


125 


1,500 


3,140 


5,910 


12,100 


18,200 


35,000 


55,800 


98,700 


201,000 


150 


1,360 


2,840 


5,360 


11,000 


16,500 


31,700 


50,600 


89,400 


182,000 


175 


1,250 


2,620 


4,930 


10,100 


15,200 


29,200 


46,500 


82,300 


167,800 


200 


1,160 


2,430 


4,580 


9,410 


14,100 


27,200 


43,300 


76,500 


156,100 


250 


1,030 


2,160 


4,060 


8,340 


12,500 


24,100 


38,400 


67,800 


138,400 


300 


935 


1,950 


3,680 


7,560 


11,300 


21,800 


34,800 


61,500 


125,400 


350 


860 


1,800 


3,390 


6,950 


10,400 


20,100 


32,000 


56,500 


115,300 


400 


800 


1,670 


3,150 


6,470 


9,690 


18,700 


29,800 


52,600 


107,300 


450 


751 


1,570 


2,960 


6,070 


9,090 


17,500 


27,900 


49,400 


100,700 


500 


709 


1,480 


2,790 


5,730 


8,590 


16,500 


26,400 


46,600 


95,100 


550 


673 


1,410 


2,650 


5,450 


8,160 


15,700 


25,000 


44,300 


90,300 


600 


642 


1,340 


2,530 


5,200 


7,780 


15,000 


23,900 


42,200 


86,200 


650 


615 


1,290 


2,420 


4,980 


7,450 


14,400 


22,900 


40,500 


82,500 


700 


591 


1,240 


2,330 


4,780 


7,160 


13,800 


22,000 


38,900 


79,300 


750 


569 


1,190 


2,240 


4,600 


6,900 


13,300 


21,200 


37,400 


76,400 


800 


550 


1,150 


2,170 


4,450 


6,660 


12,800 


20,500 


36,200 


73,700 


850 


532 


1,110 


2,100 


4,300 


6,450 


12,400 


19,800 


35,000 


71,400 


900 


516 


1,080 


2,030 


4,170 


6,250 


12,000 


19,200 


33,900 


69,200 


950 


501 


1,050 


1,970 


4,050 


6,070 


11,700 


18,600 


32,900 


67,200 


1,000 


487 


1,020 


1,920 


3,940 


5,900 


11,400 


18,100 


32,000 


65,400 


1,100 


463 


968 


1,820 


3,740 


5,610 


10,800 


17,200 


30,400 


62,100 


1,200 


442 


923 


1,740 


3,570 


5,350 


10,300 


16,400 


29,000 


59,200 


1,300 


423 


884 


1,670 


3,420 


5,120 


9,870 


15,700 


27,800 


56,700 


1,400 


406 


849 


1,600 


3,280 


4,920 


9,480 


15,100 


26,700 


54,500 


1,500 


391 


818 


1,540 


3,160 


4,740 


9,130 


14,600 


25,700 


52,500 


1,600 


378 


790 


1,490 


3,060 


4,580 


8,820 


14,100 


24,800 


50,700 


1,700 


366 


765 


1,440 


2,960 


4,430 


8,530 


13,600 


24,000 


49,000 


1,800 


355 


741 


1,400 


2,870 


4,300 


8,270 


13,200 


23,300 


47,600 


1,900 


344 


720 


1,360 


2,780 


4,170 


8,040 


12,800 


22,600 


46,200 


2,000 


335 


700 


1,320 


2,710 


4,060 


7,820 


12,500 


22,000 


44,900 



Note: AH table entries are rounded to 3 significant digits. 



2006 Edition 



54-46 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-46 



Table 6.3(c) Schedule 40 Metallic Pipe 















Gas: 


Undiluted Propane 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


1.50 




Pipe Size (in.) 


Nominal: 


Vt 


% 


1 


W* 


1V4 


2 


VA 


3 


4 


Actual ID: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 








Capacity in 


Thousands of Btu per Hour 








10 


2,680 


5,590 


10,500 


21,600 


32,400 


62,400 


99,500 


176,000 


359,000 


20 


1,840 


3,850 


7,240 


14,900 


22,300 


42,900 


68,400 


121,000 


247,000 


30 


1,480 


3,090 


5,820 


11,900 


17,900 


34,500 


54,900 


97,100 


198,000 


40 


1,260 


2,640 


4,980 


10,200 


15,300 


29,500 


47,000 


83,100 


170,000 


50 


1,120 


2,340 


4,410 


9,060 


13,600 


26,100 


41,700 


73,700 


150,000 


60 


1,010 


2,120 


4,000 


8,210 


12,300 


23,700 


37,700 


66,700 


136,000 


70 


934 


1,950 


3,680 


7,550 


11,300 


21,800 


34,700 


61,400 


125,000 


80 


869 


1,820 


3,420 


7,020 


10,500 


20,300 


32,300 


57,100 


116,000 


90 


815 


1,700 


3,210 


6,590 


9,880 


19,000 


30,300 


53,600 


109,000 


100 


770 


1,610 


3,030 


6,230 


9,330 


18,000 


28,600 


50,600 


103,000 


125 


682 


1,430 


2,690 


5,520 


8,270 


15,900 


25,400 


44,900 


91,500 


150 


618 


1,290 


2,440 


5,000 


7,490 


14,400 


23,000 


40,700 


82,900 


175 


569 


1,190 


2,240 


4,600 


6,890 


13,300 


21,200 


37,400 


76,300 


200 


529 


1,110 


2,080 


4,280 


6,410 


12,300 


19,700 


34,800 


71,000 


250 


469 


981 


1,850 


3,790 


5,680 


10,900 


17,400 


30,800 


62,900 


300 


425 


889 


1,670 


3,440 


5,150 


9,920 


15,800 


27,900 


57,000 


350 


391 


817 


1,540 


3,160 


4,740 


9,120 


14,500 


25,700 


52,400 


400 


364 


760 


1,430 


2,940 


4,410 


8,490 


13,500 


23,900 


48,800 


450 


341 


714 


1,340 


2,760 


4,130 


7,960 


12,700 


22,400 


45,800 


500 


322 


674 


1,270 


2,610 


3,910 


7,520 


12,000 


21,200 


43,200 


550 


306 


640 


1,210 


2,480 


3,710 


7,140 


11,400 


20,100 


41,100 


600 


292 


611 


1,150 


2,360 


3,540 


6,820 


10,900 


19,200 


39,200 


650 


280 


585 


1,100 


2,260 


3,390 


6,530 


10,400 


18,400 


37,500 


700 


269 


562 


1,060 


2,170 


3,260 


6,270 


9,990 


17,700 


36,000 


750 


259 


541 


1,020 


2,090 


3,140 


6,040 


9,630 


17,000 


34,700 


800 


250 


523 


985 


2,020 


3,030 


5,830 


9,300 


16,400 


33,500 


850 


242 


506 


953 


1,960 


2,930 


5,640 


9,000 


15,900 


32,400 


900 


235 


490 


924 


1,900 


2,840 


5,470 


8,720 


15,400 


31,500 


950 


228 


476 


897 


1,840 


2,760 


5,310 


8,470 


15,000 


30,500 


1,000 


222 


463 


873 


1,790 


2,680 


5,170 


8,240 


14,600 


29,700 


1,100 


210 


440 


829 


1,700 


2,550 


4,910 


7,830 


13,800 


28,200 


1,200 


201 


420 


791 


1,620 


2,430 


4,680 


7,470 


13,200 


26,900 


1,300 


192 


402 


757 


1,550 


2,330 


4,490 


7,150 


12,600 


25,800 


1,400 


185 


386 


727 


1,490 


2,240 


4,310 


6,870 


12,100 


24,800 


1,500 


178. 


372 


701 


1,440 


2,160 


4,150 


6,620 


11,700 


23,900 


1,600 


172 


359 


677 


1,390 


2,080 


4,010 


6,390 


11,300 


23,000 


1,700 


166 


348 


655 


1,340 


2,010 


3,880 


6,180 


10,900 


22,300 


1,800 


161 


337 


635 


1,300 


1,950 


3,760 


6,000 


10,600 


21,600 


1,900 


157 


327 


617 


1,270 


1,900 


3,650 


5,820 


10,300 


21,000 


2,000 


152 


318 


600 


1,230 


1,840 


3,550 


5,660 


10,000 


20,400 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-47 



PIPE SIZING 



54-47 



Table 6.3(d) Schedule 40 Metallic Pipe 



Gas: 



Inlet Pressure: 



Pressure Drop: 



Specific Gravity: 



Undiluted Propane 



11.0 in. w.c. 



0.5 in. w.c. 



1.50 





...... 


SPECIAL USE: Pipe Sizing lk-fween .Stogteor (Second Stage (lxw Pressure Uegu!,it«r) and Appliance 






Pipe Size (in.) 


Nominal 




















Inside: 


'/i 


% 


1 


1V4 


VA 


2 


2'/2 


3 


4 


Actual: 


0.622 


0.824 


1.049 


1.380 


1.610 


2.067 


2.469 


3.068 


4.026 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


291 


608 


1,150 


2,350 


3,520 


6,790 


10,800 


19,100 


39,000 


20 


200 


418 


787 


1,620 


2,420 


4,660 


7,430 


13,100 


26,800 


30 


160 


336 


632 


1,300 


1,940 


3,750 


5,970 


10,600 


21,500 


40 


137 


287 


541 


1,110 


1,660 


3,210 


5,110 


9,030 


18,400 


50 


122 


255 


480 


985 


1,480 


2,840 


4,530 


8,000 


16,300 


60 


110 


231 


434 


892 


1,340 


2,570 


4,100 


7,250 


14,800 


80 


101 


212 


400 


821 


1,230 


2,370 


3,770 


6,670 


13,600 


100 


94 


197 


372 


763 


1,140 


2,200 


3,510 


6,210 


12,700 


125 


89 


185 


349 


716 


1,070 


2,070 


3,290 


5,820 


11,900 


150 


84 


175 


330 


677 


1,010 


1,950 


3,110 


5,500 


11,200 


175 


74 


155 


292 


600 


899 


1,730 


2,760 


4,880 


9,950 


200 


67 


140 


265 


543 


814 


1,570 


2,500 


4,420 


9,010 


250 


62 


129 


243 


500 


749 


1,440 


2,300 


4,060 


8,290 


300 


58 


120 


227 


465 


697 


1,340 


2,140 


3,780 


7,710 


350 


51 


107 


201 


412 


618 


1,190 


1,900 


3,350 


6,840 


400 


46 


97 


182 


373 


560 


1,080 


1,720 


3,040 


6,190 


450 


42 


89 


167 


344 


515 


991 


1,580 


2,790 


5,700 


500 


40 


83 


156 


320 


479 


922 


1,470 


2,600 


5,300 


550 


37 


78 


146 


300 


449 


865 


1,380 


2,440 


4,970 


600 


35 


73 


138 


283 


424 


817 


1,300 


2,300 


4,700 


650 


33 


70 


131 


269 


403 


776 


1,240 


2,190 


4,460 


700 


32 


66 


125 


257 


385 


741 


1,180 


2,090 


4,260 


750 


30 


64 


120 


246 


368 


709 


1,130 


2,000 


4,080 


800 


29 


61 


115 


236 


354 


681 


1,090 


1,920 


3,920 


850 


28 


59 


111 


227 


341 


656 


1,050 


1,850 


3,770 


900 


27 


57 


107 


220 


329 


634 


1,010 


1,790 


3,640 


950 


26 


55 


104 


213 


319 


613 


978 


1,730 


3,530 


1,000 


25 


53 


100 


206 


309 


595 


948 


1,680 


3,420 


1,100 


25 


52 


97 


200 


300 


578 


921 


1,630 


3,320 


1,200 


24 


50 


95 


195 


292 


562 


895 


1,580 


3,230 


1,300 


23 


48 


90 


185 


277 


534 


850 


1,500 


3,070 


1,400 


22 


46 


86 


176 


264 


509 


811 


1,430 


2,930 


1,500 


21 


44 


82 


169 


253 


487 


777 


1,370 


2,800 


1,600 


20 


42 


79 


162 


243 


468 


746 


1,320 


2,690 


1,700 


19 


40 


76 


156 


234 


451 


719 


1,270 


2,590 


1,800 


19 


39 


74 


151 


226 


436 


694 


1,230 


2,500 


1,900 


18 


38 


71 


146 


219 


422 


672 


1,190 


2,420 


2,000 


18 


37 


69 


142 


212 


409 


652 


1,150 


2,350 



| Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-48 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-48 



Table 6.3(e) Semi-Rigid Copper Tubing 







Gas: 


Undiluted Propane 




Inlet Pressure: 


10.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


1.50 




Sl'ECIAI |iSE- Tulwfeiang llt-twon FirM Stage {lughlV-wurrKpgulairo) tiffd Second Stage (In™ Pressure Regulator) 



Tube Size (in.) 





K&L: 


Vi 


y 8 


Vi 


Va 


% 


1 


IVi 


IVi 


2 


Nominal: 
























ACR: 


% 


■/» 


y 8 


>A 


'/a 


l'/s 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


513 


1,060 


2,150 


3,760 


5,330 


11,400 


20,500 


32,300 


67,400 


20 


352 


727 


1,480 


2,580 


3,670 


7,830 


14,100 


22,200 


46,300 


30 


283 


584 


1,190 


2,080 


2,940 


6,290 


11,300 


17,900 


37,200 


40 


242 


500 


1,020 


1,780 


2,520 


5,380 


9,690 


15,300 


31,800 


50 


215 


443 


901 


1,570 


2,230 


4,770 


8,590 


13,500 


28,200 


60 


194 


401 


816 


1,430 


2,020 


4,320 


7,780 


12,300 


25,600 


70 


179 


369 


751 


1,310 


1,860 


3,980 


7,160 


11,300 


23,500 


80 


166 


343 


699 


1,220 


1,730 


3,700 


6,660 


10,500 


21,900 


90 


156 


322 


655 


1,150 


1,630 


3,470 


6,250 


9,850 


20,500 


100 


147 


304 


619 


1,080 


1,540 


3,280 


5,900 


9,310 


19,400 


125 


131 


270 


549 


959 


1,360 


2,910 


5,230 


8,250 


17,200 


150 


118 


244 


497 


869 


1,230 


2,630 


4,740 


7,470 


15,600 


175 


109 


225 


457 


799 


1,130 


2,420 


4,360 


6,880 


14,300 


200 


101 


209 


426 


744 


1,060 


2,250 


4,060 


6,400 


13,300 


250 


90 


185 


377 


659 


935 


2,000 


3,600 


5,670 


11,800 


300 


81 


168 


342 


597 


847 


1,810 


3,260 


5,140 


10,700 


350 


75 


155 


314 


549 


779 


1,660 


3,000 


4,730 


9,840 


400 


70 


144 


292 


511 


725 


1,550 


2,790 


4,400 


9,160 


450 


65 


135 


274 


480 


680 


1,450 


2,620 


4,130 


8,590 


500 


62 


127 


259 


453 


643 


1,370 


2,470 


3,900 


8,120 


550 


59 


121 


246 


430 


610 


1,300 


2,350 


3,700 


7,710 


600 


56 


115 


235 


410 


582 


i,240 


2,240 


3,530 


7,350 


650 


54 


111 


225 


393 


558 


1,190 


2,140 


3,380 


7,040 


700 


51 


106 


216 


378 


536 


1,140 


2,060 


3,250 


6,770 


750 


50 


102 


208 


364 


516 


1,100 


1,980 


3,130 


6,520 


800 


48 


99 


201 


351 


498 


1,060 


1,920 


3,020 


6,290 


850 


46 


96 


195 


340 


482 


1,030 


1,850 


2,920 


6,090 


900 


45 


93 


189 


330 


468 


1,000 


1,800 


2,840 


5,910 


950 


44 


90 


183 


320 


454 


970 


1,750 


2,750 


5,730 


1,000 


42 


88 


178 


311 


442 


944 


1,700 


2,680 


5,580 


1,100 


40 


83 


169 


296 


420 


896 


1,610 


2,540 


5,300 


1,200 


38 


79 


161 


282 


400 


855 


1,540 


2,430 


5,050 


1,300 


37 


76 


155 


270 


383 


819 


1,470 


2,320 


4,840 


1,400 


35 


73 


148 


260 


368 


787 


1,420 


2,230 


4,650 


1,500 


34 


70 


143 


250 


355 


758 


1,360 


2,150 


4,480 


1,600 


33 


68 


138 


241 


343 


732 


1,320 


2,080 


4,330 


1,700 


32 


66 


134 


234 


331 


708 


1,270 


2,010 


4,190 


1,800 


31 


64 


130 


227 


321 


687 


1,240 


1,950 


4,060 


1,900 


30 


62 


126 


220 


312 


667 


1,200 


1,890 


3,940 


2,000 


29 


60 


122 


214 


304 


648 


1,170 


1,840 


3,830 



Note: All table entries are rounded to 3 significant digits. 

'Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223. 1-49 



PIPE SIZING 



54^19 



Table 6.3(f) Semi-Rigid Copper Tubing 





Gas: 


Undiluted Propane 




Inlet Pressure: 


11.0 in. w.c. 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


1.50 









H'fcC&Al USE: Vnbt ^TiiigBi^VeeaSf^ : or V*cr* c\ Siiv' (1 *w Fu^or* t^pii uh) *md Apnsls^c^ 



Tube Size (in.) 





K&L: 


V* 


% 


vs. 


y 8 


% 


1 


VA 


\'/z 


2 


Nominal: 
























ACR: 


% 


Vi 


% 


% 


% 


l'/s 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Thousands of Btu pen- Hour 


10 


45 


93 


188 


329 


467 


997 


1,800 


2,830 


5,890 


20 


31 


64 


129 


226 


321 


685 


1,230 


1,950 


4,050 


30 


25 


51 


104 


182 


258 


550 


991 


1,560 


3,250 


40 


21 


44 


89 


155 


220 


471 


848 


1,340 


2,780 


50 


19 


39 


79 


138 


195 


417 


752 


1,180 


2,470 


60 


17 


35 


71 


125 


177 


378 


681 


1,070 


2,240 


70 


16 


32 


66 


115 


163 


348 


626 


988 


2,060 


80 


15 


30 


61 


107 


152 


324 


583 


919 


1,910 


90 


14 


28 


57 


100 


142 


304 


547 


862 


1,800 


100 


13 


27 


54 


95 


134 


287 


517 


814 


1,700 


125 


11 


24 


48 


84 


119 


254 


458 


722 


1,500 


150 


10 


21 


44 


76 


108 


230 


415 


654 


1,360 


175 


NA 


20 


40 


70 


99 


212 


382 


602 


1,250 


200 


NA 


18 


37 


65 


92 


197 


355 


560 


1,170 


250 


NA 


16 


33 


58 


82 


175 


315 


496 


1,030 


300 


NA 


15 


30 


52 


74 


158 


285 


449 


936 


350 


NA 


14 


28 


48 


68 


146 


262 


414 


861 


400 


NA 


13 


26 


45 


63 


136 


244 


385 


801 


450 


NA 


12 


24 


42 


60 


127 


229 


361 


752 


500 


NA 


11 


23 


40 


56 


120 


216 


341 


710 


550 


NA 


11 


22 


38 


53 


114 


205 


324 


674 


600 


NA 


10 


21 


36 


51 


109 


196 


309 


643 


650 


NA 


NA 


20 


34 


49 


104 


188 


296 


616 


700 


NA 


NA 


19 


33 


47 


100 


180 


284 


592 


750 


NA 


NA 


18 


32 


45 


96 


174 


274 


570 


800 


NA 


NA 


18 


31 


44 


93 


168 


264 


551 


850 


NA 


NA 


17 


30 


42 


90 


162 


256 


533 


900 


NA 


NA 


17 


29 


41 


87 


157 


248 


517 


950 


NA 


NA 


16 


28 


40 


85 


153 


241 


502 


1,000 


NA 


NA 


16 


27 


39 


83 


149 


234 


488 


1,100 


NA 


NA 


15 


26 


37 


78 


141 


223 


464 


1,200 


NA 


NA 


14 


25 


35 


75 


135 


212 


442 


1,300 


NA 


NA 


14 


24 


34 


72 


129 


203 


423 


1,400 


NA 


NA 


13 


23 


32 


69 


124 


195 


407 


1,500 


NA 


NA 


13 


22 


31 


66 


119 


188 


392 


1,600 


NA 


NA 


12 


21 


30 


64 


115 


182 


378 


1,700 


NA 


NA 


12 


20 


29 


62 


112 


176 


366 


1,800 


NA 


NA 


11 


20 


28 


60 


108 


170 


355 


1,900 


NA 


NA 


11 


19 


27 


58 


105 


166 


345 


2,000 


NA 


NA 


11 


19 


27 


57 


102 


161 


335 



NA means a flow of less than 10,000 Btu/hr. 

Note: All table entries are rounded to 3 significant digits. 

"Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



54-50 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-50 



Table 6.3(g) Semi-Rigid Copper Tubing 

















Gas: 


Undiluted Propane 




Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 






Specific Gravity: 


1.50 




Tube Size (in.) 




K&L: 


1/4 


% 


'A 


% 


>A 


1 


V/t 


1*4 


2 


























ACR: 


3 /s 


Vl 


% 


% 


% 


l'/s 


1% 


— 


— 


Outside: 


0.375 


0.500 


0.625 


0.750 


0.875 


1.125 


1.375 


1.625 


2.125 


Inside:* 


0.305 


0.402 


0.527 


0.652 


0.745 


0.995 


1.245 


1.481 


1.959 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


413 


852 


1,730 


3,030 


4,300 


9,170 


16,500 


26,000 


54,200 


20 


284 


585 


1,190 


2,080 


2,950 


6,310 


11,400 


17,900 


37,300 


30 


228 


470 


956 


1,670 


2,370 


5,060 


9,120 


14,400 


29,900 


40 


195 


402 


818 


1,430 


2,030 


4,330 


7,800 


12,300 


25,600 


50 


173 


356 


725 


1,270 


1,800 


3,840 


6,920 


10,900 


22,700 


60 


157 


323 


657 


1,150 


1,630 


3,480 


6,270 


9,880 


20,600 


70 


144 


297 


605 


1,060 


1,500 


3,200 


5,760 


9,090 


18,900 


80 


134 


276 


562 


983 


1,390 


2,980 


5,360 


8,450 


17,600 


90 


126 


259 


528 


922 


1,310 


2,790 


5,030 


7,930 


16,500 


100 


119 


245 


498 


871 


1,240 


2,640 


4,750 


7,490 


15,600 


125 


105 


217 


442 


772 


1,100 


2,340 


4,210 


6,640 


13,800 


150 


95 


197 


400 


700 


992 


2,120 


3,820 


6,020 


12,500 


175 


88 


181 


368 


644 


913 


1,950 


3,510 


5,540 


11,500 


200 


82 


168 


343 


599 


849 


1,810 


3,270 


5,150 


10,700 


250 


72 


149 


304 


531 


753 


1,610 


2,900 


4,560 


9,510 


300 


66 


135 


275 


481 


682 


1,460 


2,620 


4,140 


8,610 


350 


60 


124 


253 


442 


628 


1,340 


2,410 


3,800 


7,920 


400 


56 


116 


235 


411 


584 


1,250 


2,250 


3,540 


7,370 


450 


53 


109 


221 


386 


548 


1,170 


2,110 


3,320 


6,920 


500 


50 


103 


209 


365 


517 


1,110 


1,990 


3,140 


6,530 


550 


47 


97 


198 


346 


491 


1,050 


1,890 


2,980 


6,210 


600 


45 


93 


189 


330 


469 


1,000 


1,800 


2,840 


5,920 


650 


43 


89 


181 


316 


449 


959 


1,730 


2,720 


5,670 


700 


41 


86 


174 


304 


431 


921 


1,660 


2,620 


5,450 


750 


40 


82 


168 


293 


415 


888 


1,600 


2,520 


5,250 


800 


39 


80 


162 


283 


401 


857 


1,540 


2,430 


5,070 


850 


37 


77 


157 


274 


388 


829 


1,490 


2,350 


4,900 


900 


36 


75 


152 


265 


376 


804 


1,450 


2,280 


4,750 


950 


35 


72 


147 


258 


366 


781 


1,410 


2,220 


4,620 


1,000 


34 


71 


143 


251 


356 


760 


1,370 


2,160 


4,490 


1,100 


32 


67 


136 


238 


338 


721 


1,300 


2,050 


4,270 


1,200 


31 


64 


130 


227 


322 


688 


1,240 


1,950 


4,070 


1,300 


30 


61 


124 


217 


309 


659 


1,190 


1,870 


3,900 


1,400 


28 


59 


120 


209 


296 


633 


1,140 


1,800 


3,740 


1,500 


27 


57 


115 


201 


286 


610 


1,100 


1,730 


3,610 


1,600 


26 


55 


111 


194 


276 


589 


1,060 


1,670 


3,480 


1,700 


26 


53 


108 


188 


267 


570 


1,030 


1,620 


3,370 


1,800 


25 


51 


104 


182 


259 


553 


1,000 


1,570 


3,270 


1,900 


24 


50 


101 


177 


251 


537 


966 


1,520 


3,170 


2,000 


23 


48 


99 


172 


244 


522 


940 


1,480 


3,090 



Note: All table entries are rounded to 3 significant digits. 

'Table capacities are based on Type K copper tubing inside diameter (shown) , which has the smallest inside 

diameter of the copper tubing products. 



2006 Edition 



ANSI Z223.1-51 



PIPE SIZING 



54-51 



Table 6.3(h) Corrugated 


Stainless Steel Tubing (CSST) 




























Gas: 


Undiluted 


Propane 




Inlet Pressure: 


11.0 in. w.c. 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


1.50 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Thousands of Btu per Hour 


5 


72 


99 


181 


211 


355 


426 


744 


863 


1,420 


2,830 


3,270 


5,780 


6,550 


10 


50 


69 


129 


150 


254 


303 


521 


605 


971 


1,990 


2,320 


4,110 


4,640 


15 


39 


55 


104 


121 


208 


248 


422 


490 


775 


1,620 


1,900 


3,370 


3,790 


20 


34 


49 


91 


106 


183 


216 


365 


425 


661 


1,400 


1,650 


2,930 


3,290 


25 


30 


42 


82 


94 


164 


192 


325 


379 


583 


1,250 


1,480 


2,630 


2,940 


30 


28 


39 


74 


87 


151 


177 


297 


344 


528 


1,140 


1,350 


2,400 


2,680 


40 


23 


33 


64 


74 


131 


153 


256 


297 


449 


988 


1,170 


2,090 


2,330 


50 


20 


30 


58 


66 


118 


137 


227 


265 


397 


884 


1,050 


1,870 


2,080 


60 


19 


26 


53 


60 


107 


126 


207 


241 


359 


805 


961 


1,710 


1,900 


70 


17 


25 


49 


57 


99 


117 


191 


222 


330 


745 


890 


1,590 


1,760 


80 


15 


23 


45 


52 


94 


109 


178 


208 


307 


696 


833 


1,490 


1,650 


90 


15 


22 


44 


50 


90 


102 


169 


197 


286 


656 


787 


1,400 


1,550 


100 


14 


20 


41 


47 


85 


98 


159 


186 


270 


621 


746 


1,330 


1,480 


150 


11 


15 


31 


36 


66 


75 


123 


143 


217 


506 


611 


1,090 


1,210 


200 


9 


14 


28 


33 


60 


69 


112 


129 


183 


438 


531 


948 


1,050 


250 


8 


12 


25 


30 


53 


61 


99 


117 


163 


390 


476 


850 


934 


300 


8 


11 


23 


26 


50 


57 


90 


107 


147 


357 


434 


777 


854 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table includes losses for four 90 degree bends and two end fittings. Tubing runs with larger numbers of 
bends and/or fittings shall be increased by an equivalent length of tubing to the following equation: L= 1.3n, 
where L is additional length (ft) of tubing and n is the number of additional fittings and/or bends. 

(2) All table entries are rounded to 3 significant digits. 



2006 Edition 



54-52 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-52 



Table 6.3(i) Corrugated Stainless Steel Tubing (CSST) 























Gas: 


Undiluted 


Propane 






Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


1.50 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


426 


558 


927 


1,110 


1,740 


2,170 


4,100 


4,720 


7,130 


15,200 


16,800 


29,400 


34,200 


25 


262 


347 


591 


701 


1,120 


1,380 


2,560 


2,950 


4,560 


9,550 


10,700 


18,800 


21,700 


30 


238 


316 


540 


640 


1,030 


1,270 


2,330 


. 2,690 


4,180 


8,710 


9,790 


17,200 


19,800 


40 


203 


271 


469 


554 


896 


1,100 


2,010 


2,320 


3,630 


7,530 


8,500 


14,900 


17,200 


50 


181 


243 


420 


496 


806 


986 


1,790 


2,070 


3,260 


6,730 


7,610 


13,400 


15,400 


75 


147 


196 


344 


406 


663 


809 


1,460 


1,690 


2,680 


5,480 


6,230 


11,000 


12,600 


80 


140 


189 


333 


393 


643 


768 


1,410 


1,630 


2,590 


5,300 


6,040 


10,600 


12,200 


100 


124 


169 


298 


350 


578 


703 


1,260 


1,450 


2,330 


4,740 


5,410 


9,530 


10,900 


150 


101 


137 


245 


287 


477 


575 


1,020 


1,180 


1,910 


3,860 


4,430 


7,810 


8,890 


200 


86 


118 


213 


248 


415 


501 


880 


1,020 


1,660 


3,340 


3,840 


6,780 


7,710 


250 


77 


105 


191 


222 


373 


448 


785 


910 


1,490 


2,980 


3,440 


6,080 


6,900 


300 


69 


96 


173 


203 


343 


411 


716 


829 


1,360 


2,720 


3,150 


5,560 


6,300 


400 


60 


82 


151 


175 


298 


355 


616 


716 


1,160 


2,350 


2,730 


4,830 


5,460 


500 


53 


72 


135 


158 


268 


319 


550 


638 


1,030 


2,100 


2,450 


4,330 


4,880 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 
V2 psi (based on 13 in. w.c. outlet pressure), do not use this table. Consult with regulator manufacturer for 
pressure drops and capacity factors. Pressure drops across a regulator may vary with flow rate. 

(2) CAUTION: Capacities shown in table may exceed maximum capacity for a selected regulator. Consult 
with regulator or tubing manufacturer for guidance. 

(3) Table includes losses for four 90 degree bends and two end fittings. Tubing runs with larger number of 
bends and/or fittings shall be increased by an equivalent length of tubing according to the following equa- 
tion: L - 1.3n, where L is additional length (ft) of tubing and n is the number of additional fittings and/or 
bends. 

(4) All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-53 



PIPE SIZING 



54-53 



Table 6.3(j) Corrugated Stainless Steel Tubing (CSST) 























Gas: 


Undiluted 


Propane 






Inlet Pressure: 


5.0 psi 




Pressure Drop: 


3.5 psi 




Specific Gravity: 


1.50 




Tube Size (EHD)* 


Flow Designation: 


13 


15 


18 


19 


23 


25 


30 


31 


37 


46 


48 


60 


62 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


826 


1,070 


1,710 


2,060 


3,150 


4,000 


7,830 


8,950 


13,100 


28,600 


31,200 


54,400 


63,800 


25 


509 


664 


1,090 


1,310 


2,040 


2,550 


4,860 


5,600 


8,400 


18,000 


19,900 


34,700 


40,400 


30 


461 


603 


999 


1,190 


1,870 


2,340 


4,430 


5,100 


7,680 


16,400 


18,200 


31,700 


36,900 


40 


396 


520 


867 


1,030 


1,630 


2,030 


3,820 


4,400 


6,680 


14,200 


15,800 


27,600 


32,000 


50 


352 


463 


777 


926 


1,460 


1,820 


3,410 


3,930 


5,990 


12,700 


14,100 


24,700 


28,600 


75 


284 


376 


637 


757 


1,210 


1,490 


2,770 


3,190 


4,920 


10,300 


11,600 


20,300 


23,400 


80 


275 


363 


618 


731 


1,170 


1,450 


2,680 


3,090 


4,770 


9,990 


11,200 


19,600 


22,700 


100 


243 


324 


553 


656 


1,050 


1,300 


2,390 


2,760 


4,280 


8,930 


10,000 


17,600 


20,300 


150 


196 


262 


453 


535 


866 


1,060 


1,940 


2,240 


3,510 


7,270 


8,210 


14,400 


16,600 


200 


169 


226 


393 


464 


755 


923 


1,680 


1,930 


3,050 


6,290 


7,130 


12,500 


14,400 


250 


150 


202 


352 


415 


679 


828 


1,490 


1,730 


2,740 


5,620 


6,390 


11,200 


12,900 


300 


136 


183 


322 


379 


622 


757 


1,360 


1,570 


2,510 


5,120 


5,840 


10,300 


11,700 


400 


117 


158 


279 


328 


542 


657 


1,170 


1,360 


2,180 


4,430 


5,070 


8,920 


10,200 


500 


104 


140 


251 


294 


488 


589 


1,050 


1,210 


1,950 


3,960 


4,540 


8,000 


9,110 



*EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between 

different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing. 

Notes: 

(1) Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 
X A psi (based on 13 in. w.c. outlet pressure), do not use this table. Consult with regulator manufacturer for 
pressure drops and capacity factors. Pressure drops across a regulator may vary with flow rate. 

(2) CAUTION: Capacities shown in table may exceed maximum capacity for a selected regulator. Consult 
with regulator or tubing manufacturer for guidance. 

(3) Table includes losses for four 90 degree bends and two end fittings. Tubing runs with larger number of 
bends and/or fittings shall be increased by an equivalent length of tubing according to the following equa- 
tion: L = 1 .3n, where L is additional length (ft) of tubing and n is the number of additional fittings and/or 
bends. 

(4) All table entries are rounded to 3 significant digits. 



2006 Edition 



54-54 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-54 



Table 6.3 (k) Polyethylene Plastic Pipe 













Gas: 


Undiluted Propane 






Inlet Pressure: 


11.0 in. w.c. 




Pressure Drop: 


0.5 in. w.c. 




Specific Gravity: 


1.50 




Pipe Size (in.) 


Nominal OD: 


V4 


3 /4 


1 


1V4 


V/2 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR U. 00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID: 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


340 


680 


1,230 


2,130 


3,210 


5,770 


20 


233 


468 


844 


1,460 


2,210 


3,970 


30 


187 


375 


677 


1,170 


1,770 


3,180 


40 


160 


321 


580 


1,000 


1,520 


2,730 


50 


142 


285 


514 


890 


1,340 


2,420 


60 


129 


258 


466 


807 


1,220 


2,190 


70 


119 


237 


428 


742 


1,120 


2,010 


80 


110 


221 


398 


690 


1,040 


1,870 


90 


103 


207 


374 


648 


978 


1,760 


100 


98 


196 


353 


612 


924 


1,660 


125 


87 


173 


313 


542 


819 


1,470 


150 


78 


157 


284 


491 


742 


1,330 


175 


72 


145 


261 


452 


683 


1,230 


200 


67 


135 


243 


420 


635 


1,140 


250 


60 


119 


215 


373 


563 


1,010 


300 


54 


108 


195 


338 


510 


916 


350 


50 


99 


179 


311 


469 


843 


400 


46 


92 


167 


289 


436 


784 


450 


43 


87 


157 


271 


409 


736 


500 


41 


82 


148 


256 


387 


695 



Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



ANSI Z223.1-55 



PIPE SIZING 



54-55 



Table 6.3(1) Polyethylene Plastic Pipe 













Gas: 


Undiluted Propane 






Inlet Pressure: 


2.0 psi 




Pressure Drop: 


1.0 psi 




Specific Gravity: 


1.50 








Pipe Size (in.) 






Nominal OD: 


'/•> 


¥■> 


1 


l>/4 


1V4 


2 


Designation: 


SDR 9.33 


SDR 11.0 


SDR 11.00 


SDR 10.00 


SDR 11.00 


SDR 11.00 


Actual ID: 


0.660 


0.860 


1.077 


1.328 


1.554 


1.943 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


3,130 


6,260 


11,300 


19,600 


29,500 


53,100 


20 


2,150 


4,300 


7,760 


13,400 


20,300 


36,500 


30 


1,730 


3,450 


6,230 


10,800 


16,300 


29,300 


40 


1,480 


2,960 


5,330 


9,240 


14,000 


25,100 


50 


1,310 


2,620 


4,730 


8,190 


12,400 


22,200 


60 


1,190 


2,370 


4,280 


7,420 


11,200 


20,100 


70 


1,090 


2,180 


3,940 


6,830 


10,300 


18,500 


80 


1,010 


2,030 


3,670 


6,350 


9,590 


17,200 


90 


952 


1,910 


3,440 


5,960 


9,000 


16,200 


100 


899 


1,800 


3,250 


5,630 


8,500 


15,300 


125 


797 


1,600 


2,880 


4,990 


7,530 


13,500 


150 


722 


1,450 


2,610 


4,520 


6,830 


12,300 


175 


664 


1,330 


2,400 


4,160 


6,280 


11,300 


200 


618 


1,240 


2,230 


3,870 


5,840 


10,500 


250 


548 


1,100 


1,980 


3,430 


5,180 


9,300 


300 


496 


994 


1,790 


3,110 


4,690 


8,430 


350 


457 


914 


1,650 


2,860 


4,320 


7,760 


400 


425 


851 


1,530 


2,660 


4,020 


7,220 


450 


399 


798 


1,440 


2,500 


3,770 


6,770 


500 


377 


754 


1,360 


2,360 


3,560 


6,390 


550 


358 


716 


1,290 


2,240 


3,380 


6,070 


600 


341 


683 


1,230 


2,140 


3,220 


5,790 


650 


327 


654 


1,180 


2,040 


3,090 


5,550 


700 


314 


628 


1,130 


1,960 


2,970 


5,330 


750 


302 


605 


1,090 


1,890 


2,860 


5,140 


800 


292 


585 


1,050 


1,830 


2,760 


4,960 


850 


283 


566 


1,020 


1,770 


2,670 


4,800 


900 


274 


549 


990 


1,710 


2,590 


4,650 


950 


266 


533 


961 


1,670 


2,520 


4,520 


1,000 


259 


518 


935 


1,620 


2,450 


4,400 


1,100 


246 


492 


888 


1,540 


2,320 


4,170 


1,200 


234 


470 


847 


1,470 


2,220 


3,980 


1,300 


225 


450 


811 


1,410 


2,120 


3,810 


1,400 


216 


432 


779 


1,350 


2,040 


3,660 


1,500 


208 


416 


751 


1,300 


1,960 


3,530 


1,600 


201 


402 


725 


1,260 


1,900 


3,410 


1,700 


194 


389 


702 


1,220 


1,840 


3,300 


1,800 


188 


377 


680 


1,180 


1,780 


3,200 


1,900 


183 


366 


661 


1,140 


1,730 


3,110 


2,000 


178 


356 


643 


1,110 


1,680 


3,020 



| Note: All table entries are rounded to 3 significant digits. 



2006 Edition 



54-56 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-56 



Table 6.3(m) Polyethylene Plastic Tubing 





Gas: 


Undiluted Propane 




Inlet Pressure: 


11.0 in. w.c. 




Pressure Drop: 


0.5 in. w.c 




Specific Gravity: 


1.50 




Plastic Tubing Size (CTS) (in.) 


Nominal OD: 


>/2 


3 /4 


Designation: 


SDR 7.00 


SDR 11.00 


Actual ID: 


0.445 


0.927 


Length (ft) 


Capacity in Thousands of Btu per Hour 


10 


121 


828 


20 


83 


569 


30 


67 


457 


40 


57 


391 


50 


51 


347 


60 


46 


314 


70 


42 


289 


80 


39 


269 


90 


37 


252 


100 


35 


238 


125 


31 


211 


150 


28 


191 


175 


26 


176 


200 


24 


164 


225 


22 


154 


250 


21 


145 


275 


20 


138 


300 


19 


132 


350 


18 


121 


400 


16 


113 


450 


15 


106 


500 


15 


100 



Table 6.4.2 Cr and Ffor Natural Gas and 
Undiluted Propane at Standard Conditions 



I Note: All table entries are rounded to 3 significant digits. 



6.4 Sizing Equations. The inside diameter of smooth wall pipe 
or tubing shall be determined by the sizing equations in 6.4.1 
and 6.4.2 using the equivalent pipe length determined by the 
methods in 6.1.1 through 6.1.3. 

6.4.1* Low-Pressure Gas Formula [Less than 1.5 psi (10.3 kPa)]: 



D-- 



19.17 



( AH 
I CrxL 



6.4.2* High-Pressure Gas Formula [1.5 psi (10.3 kPa) and 
above] : 

f)0.381 

D = - 



18.93 



CrxL 



where: 

D = inside diameter of pipe, in. 

Q = input rate appliance (s), cubic feet per hour at 
60°F and 30 in. mercury column 
Pj = upstream pressure, psia (Pj + 14.7) 
P 2 = downstream pressure, psia (P 2 + 14.7) 

L = equivalent length of pipe, ft 





Formula Factors 


Gas 


Cr Y 


Natural Gas 
Undiluted 
Propane 


0.6094 0.9992 
1.2462 0.9910 



AH = pressure drop, in. w.c. (27.7 in. H 2 = 1 psi) 
See Table 6.4.2 for values of Cr and Y. 

Chapter 7 Gas Piping Installation 

7.1 Piping Underground. 

7.1.1 Clearances. Underground gas piping shall be installed 
with sufficient clearance from any other underground struc- 
ture to avoid contact therewith, to allow maintenance, and to 
protect against damage from proximity to other structures. In 
addition, underground plastic piping shall be installed with 
sufficient clearance or shall be insulated from any source of 
heat so as to prevent the heat from impairing the serviceability 
of the pipe. 

7.1.2 Protection Against Damage. Means shall be provided to 
prevent excessive stressing of the piping where there is heavy ve- 
hicular traffic or soil conditions are unstable and setding of pip- 
ing or foundation walls could occur. Piping shall be buried or 
covered in a manner so as to protect the piping from physical 
damage. Piping shall be protected from physical damage where it 
passes through flower beds, shrub beds, and other such culti- 
vated areas where such damage is reasonably expected. 

7.1.2.1 Cover Requirements. Underground piping systems 
shall be installed with a minimum of 1 2 in. (300 mm) of cover. 

(A) The minimum cover shall be increased to 18 in. 
(460 mm) if external damage to the pipe or tubing from ex- 
ternal forces is likely to result. 

(B) Where a minimum of 12 in. (300 mm) of cover cannot be 
provided, the pipe shall be installed in conduit or bridged 
(shielded) . 

7.1.2.2 Trenches. The trench shall be graded so that the pipe 
has a firm, substantially continuous bearing on the bottom of 
the trench. 

7.1.2.3 Backfilling. Where flooding of the trench is done to 
consolidate the backfill, care shall be exercised to see that the 
pipe is not floated from its firm bearing on the trench bottom. 

7.1.3* Protection Against Corrosion. Gas piping in contact 
with earth or other material that could corrode the piping 
shall be protected against corrosion in an approved manner. 
When dissimilar metals are joined underground, an insulating 
coupling or fitting shall be used. Piping shall not be laid in 
contact with cinders. Uncoated threaded or socket welded 
joints shall not be used in piping in contact with soil or where 
internal or external crevice corrosion is known to occur. 

7.1.4* Protection Against Freezing. Where the formation of 
hydrates or ice is known to occur, piping shall be protected 
against freezing. 

7.1.5 Piping Through Foundation Wall. Underground piping, 
where installed through the outer foundation or basement 
wall of a building, shall be encased in a protective pipe. The 



2006 Edition 



ANSI Z223.1-57 



GAS PIPING INSTALLATION 



54-57 



space between the gas piping and the building shall be sealed 
to prevent entry of gas or water. 

7.1.6 Piping Underground Beneath Buildings. Where the in- 
stallation of gas piping underground beneath buildings is un- 
avoidable, the piping shall be encased in an approved conduit 
designed to withstand the superimposed loads and installed in 
accordance with 7.1.6.1 or 7.1.6.2. 

7.1.6.1 Conduit with One End Terminating Outdoors. The 

conduit shall extend into an accessible portion of the building 
and, at the point where the conduit terminates in the build- 
ing, the space between the conduit and the gas piping shall be 
sealed to prevent the possible entrance of any gas leakage. 
Where the end sealing is of a type that will retain the full 
pressure of the pipe, the conduit shall be designed for the 
same pressure as the pipe. The conduit shall extend at least 
4 in. (100 mm) outside the building, be vented outdoors 
above grade, and be installed so as to prevent the entrance of 
water and insects. 

7.1.6.2 Conduit with Both Ends Terminating Indoors. Where 
the conduit originates and terminates within the same build- 
ing, the conduit shall originate and terminate in an accessible 
portion of the building and shall not be sealed. 

7.1.7 Plastic Pipe. 

7.1.7.1 Connection of Plastic Piping. Plastic pipe shall be in- 
stalled outdoors, underground only. 

Exception No. 1: Plastic pipe shall be permitted to terminate above- 
ground where an anodeless riser is used. 

Exception No. 2: Plastic pipe shall be permitted to terminate vnth a 
wall head adapter aboveground in buildings, including basements, 
where the plastic pipe is inserted in a piping material permitted for use 
in buildings. 

7.1.7.2 Connections Between Metallic and Plastic Piping. 

Connections made outdoors and underground between me- 
tallic and plastic piping shall be made with fittings conforming 
to either of the following: 

( 1 ) ASTM D 25 1 3, Standard Specification for Thermoplastic Gas Pres- 
sure Pipe, Tubing, and Fittings, Category I transition fittings 

(2) ASTM F 1973, Standard Specification for Factory Assembled 
Anodeless Risers and Transition Fittings in Polyethylene (PE) 
and Poly amide 11 (PAH) Fuel Gas Distribution Systems 

7.1.7.3 Tracer Wire. An electrically continuous corrosion- 
resistant tracer wire (minimum AWG 14) or tape shall be bur- 
ied with the plastic pipe to facilitate locating. One end shall be 
brought aboveground at a building wall or riser. 

7.2 Installation of Piping. 

7.2.1 Piping installed aboveground shall be securely sup- 
ported and located where it will be protected from physical 
damage (also see 7.1.4). Where passing through an exterior 
wall, the piping shall also be protected against corrosion by 
coating or wrapping with an inert material approved for such 
applications. Where piping is encased in a protective pipe 
sleeve, the annular space between the gas piping and the 
sleeve shall be sealed at the wall to prevent the entry of water, 
insects, or rodents. 

7.2.2 Building Structure. 

7.2.2.1 The installation of gas piping shall not cause struc- 
tural stresses within building components to exceed allowable 
design limits. 



7.2.2.2 Approval shall be obtained before any beams or joists 
are cut or notched. 

7.2.3 Other than Dry Gas. Drips, sloping, protection from 
freezing, and branch pipe connections, as provided for in 
7.1.4, 7.6.1, and Section 7.8, shall be provided when other 
than dry gas is distributed and climatic conditions make such 
provisions necessary. 

7.2.4 Gas Piping to Be Sloped. Piping for other than dry gas 
conditions shall be sloped not less than V4 in. in 15 ft (7 mm in 
4.6 m) to prevent traps. 

7.2.5* Prohibited Locations. Gas piping inside any building 
shall not be installed in or through a clothes chute, chimney 
or gas vent, dumbwaiter, elevator shaft, or air duct, other than 
combustion air ducts. 

7.2.6 Hangers, Supports, and Anchors. 

7.2.6.1 Piping shall be supported with pipe hooks, metal pipe 
straps, bands, brackets, or hangers suitable for the size of pip- 
ing, of adequate strength and quality, and located at intervals 
so as to prevent or damp out excessive vibration. Piping shall 
be anchored to prevent undue strains on connected appli- 
ances and equipment and shall not be supported by other 
piping. Pipe hangers and supports shall conform to the re- 
quirements of ANSI/MSS SP-58, Pipe Hangers and Supports — 
Materials, Design and Manufacture. 

7.2.6.2 Spacings of supports in gas piping installations shall 
not be greater than shown in Table 7.2.6.2. Spacing of sup- 
ports of CSST shall be in accordance with the CSST manufac- 
turer's instructions. 



Table 7.2.6.2 Support of Piping 



Steel Pipe, 

Nominal 

Size of Pipe 

(in.) 


Spacing of 
Supports 

(ft) 


Nominal 

Size of 

Tubing 

Smooth-Wall 

(in. O.D.) 


Spacing of 
Supports 

(ft) 


y 2 

% or 1 
1 ] A or larger 
(horizontal) 
1V4 or larger 

(vertical) 


6 

8 

10 

Every floor 
level 


V2 

Vs or S A 

% or 1 

(horizontal) 

1 or larger 

(vertical) 


4 

6 

8 

Every floor 
level 



For SI unite, 1 ft = 0.305 m. 



7.2.6.3 Supports, hangers, and anchors shall be installed so 
as not to interfere with the free expansion and contraction of 
the piping between anchors. All parts of the supporting system 
shall be designed and installed so they will not be disengaged 
by movement of the supported piping. 

7.2.6.4 Piping on Roof Tops. Gas piping installed on the roof 
surfaces shall be elevated above the roof surface and shall be 
supported in accordance with Table 7.2.6.2. 

7.2.7 Removal of Pipe. Where piping containing gas is to be 
removed, the line shall be first disconnected from all sources 
of gas and then thoroughly purged with air, water, or inert gas 
before any cutting or welding is done. (See Section 8.3.) 



2006 Edition 



54-58 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-58 



7.2.8 CSST. CSST piping systems shall be installed in accor- 
dance with this code and the manufacturer's installation in- 
structions. 

7.3 Concealed Piping in Buildings. 

7.3.1 General. Gas piping in concealed locations shall be in- 
stalled in accordance with this section. 

7.3.2 Connections. Where gas piping is to be concealed, 
unions, tubing fittings, right and left couplings, bushings, 
swing joints, and compression couplings made by combina- 
tions of fittings shall not be used. Connections shall be of the 
following type: 

(1) Pipe fittings such as elbows, tees, and couplings 

(2) Joining tubing by brazing (see 5.6.8.2) 

(3) Fittings listed for use in concealed spaces that have been 
demonstrated to sustain, without leakage, any forces due 
to temperature expansion or contraction, vibration, or 
fatigue based on their geographic location, application, 
or operation 

(4) Where necessary to insert fittings in gas pipe that has been 
installed in a concealed location, the pipe shall be recon- 
nected by welding, flanges, or the use of a ground joint 
union with the nut center-punched to prevent loosening 
by vibration 

7.3.3 Piping in Partitions. Concealed gas piping shall not be 
located in solid partitions. 

7.3.4 Tubing in Partitions. This provision shall not apply to 
tubing that pierces walls, floors, or partitions. Tubing installed 
vertically and horizontally inside hollow walls or partitions 
without protection along its entire concealed length shall 
meet the following requirements: 

(1) A steel striker barrier not less than 0.0508 in. (1.3 mm) 
thick, or equivalent, is installed between the tubing and 
the finished wall and extends at least 4 in. (100 mm) be- 
yond concealed penetrations of plates, firestops, wall 
studs, and so on. 

(2) The tubing is installed in single runs and is not rigidly 
secured. 

7.3.5 Piping in Floors. 

7.3.5.1 Industrial Occupancies. In industrial occupancies, gas 
piping in solid floors such as concrete shall be laid in channels in 
the floor and covered to permit access to the piping with a mini- 
mum of damage to the building. Where piping in floor channels 
could be exposed to excessive moisture or corrosive substances, 
the piping shall be protected in an approved manner. 

7.3.5.2 Other Occupancies. In other than industrial occupan- 
cies and where approved by the authority havingjurisdicdon, gas 
piping embedded in concrete floor slabs constructed with port- 
land cement shall be surrounded with a minimum of \ X A in. 
(38 mm) of concrete and shall not be in physical contact with 
other metallic structures such as reinforcing rods or electrically 
neutral conductors. All piping, fittings, and risers shall be pro- 
tected against corrosion in accordance with 5.6.6. Piping shall 
not be embedded in concrete slabs containing quickset additives 
or cinder aggregate. 

7.4 Piping in Vertical Chases. Where gas piping exceeding 5 psi 
(34 kPa) is located within vertical chases in accordance with 
5.5.1(2), the requirements of 7.4.1 through 7.4.3 shall apply. 

7.4.1 Pressure Reduction. Where pressure reduction is re- 
quired in branch connections for compliance with 5.5.1, such 



reduction shall take place either inside the chase or immedi- 
ately adjacent to the outside wall of the chase. Regulator vent- 
ing and downstream overpressure protection shall comply 
with 5.8.5 and Section 5.9. The regulator shall be accessible 
for service and repair and vented in accordance with one of 
the following: 

(1) Where the fuel gas is lighter than air, regulators equipped 
with a vent-limiting means shall be permitted to be vented 
into the chase. Regulators not equipped with a vent-limiting 
means shall be permitted to be vented either directly to the 
outdoors or to a point within the top 1 ft (0.3 m) of the 
chase. 

(2) Where the fuel gas is heavier than air, the regulator vent 
shall be vented only directiy to the outdoors. 

7.4.2 Chase Construction. Chase construction shall comply 
with local building codes with respect to fire resistance and 
protection of horizontal and vertical openings. 

7.4.3* Ventilation. A chase shall be ventilated to the outdoors 
and only at the top. The opening(s) shall have a minimum 
free area (in square inches) equal to the product of one-half 
of the maximum pressure in the piping (in psi) times the larg- 
est nominal diameter of that piping (in inches) , or the cross- 
sectional area of the chase, whichever is smaller. Where more 
than one fuel gas piping system is present, the free area for 
each system shall be calculated and the largest area used. 

7.5 Gas Pipe Turns. Changes in direction of gas pipe shall be 
made by the use of fittings, factory bends, or field bends. 

7.5.1 Metallic Pipe. Metallic pipe bends shall comply with the 
following: 

(1) Bends shall be made only with bending tools and proce- 
dures intended for that purpose. 

(2) All bends shall be smooth and free from buckling, cracks, 
or other evidence of mechanical damage. 

(3) The longitudinal weld of the pipe shall be near the neu- 
tral axis of the bend. 

(4) Pipe shall not be bent through an arc of more than 90 de- 
grees. 

(5) The inside radius of a bend shall be not less than 6 times 
the outside diameter of the pipe. 

7.5.2 Plastic Pipe. Plastic pipe bends shall comply with the 
following: 

( 1 ) The pipe shall not be damaged, and the internal diameter 
of the pipe shall not be effectively reduced. 

(2) Joints shall not be located in pipe bends. 

(3) The radius of the inner curve of such bends shall not be 
less than 25 times the inside diameter of the pipe. 

(4) Where the piping manufacturer specifies the use of spe- 
cial bending tools or procedures, such tools or proce- 
dures shall be used. 

7.5.3 Elbows. Factory-made welding elbows or transverse seg- 
ments cut therefrom shall have an arc length measured along 
the crotch of at least 1 in. (25 mm) for pipe sizes 2 in. and 
larger. 

7.6 Drips and Sediment Traps. 

7.6.1 Provide Drips Where Necessary. For other than dry gas 
conditions, a drip shall be provided at any point in the line of 
pipe where condensate could collect. Where required by the 
authority havingjurisdicdon or the serving gas supplier, a drip 
shall also be provided at the outiet of the meter. This drip shall 



2006 Edition 



ANSI Z223. 1-59 



GAS PIPING INSTALLATION 



54-59 



be so installed as to constitute a trap wherein an accumulation 
of condensate will shut off the flow of gas before it will run 
back into the meter. 

7.6.2 Location of Drips. All drips shall be installed only in 
such locations that they will be readily accessible to permit 
cleaning or emptying. A drip shall not be located where the 
condensate is likely to freeze. 

7.6.3 Sediment Traps. (See 9.6.7.) 

7.7 Outlets. 

7.7.1 Location and Installation. 

7.7.1.1 The outlet fittings or piping shall be securely fastened 
in place. 

7.7.1.2 Outlets shall not be located behind doors. 

7.7.1.3 Oudets shall be located far enough from floors, walls, 
patios, slabs, and ceilings to permit the use of wrenches with- 
out straining, bending, or damaging the piping. 

7.7.1.4 The unthreaded portion of gas piping oudets shall 
extend not less than 1 in. (25 mm) through finished ceilings 
or indoor or outdoor walls. 

7.7.1.5 The unthreaded portion of gas piping oudets shall 
extend not less than 2 in. (50 mm) above the surface of floors 
or outdoor patios or slabs. 

7.7.1.6 The provisions of 7.7.1.4 and 7.7.1.5 shall not apply to 
listed quick-disconnect devices of the flush-mounted type or 
listed gas convenience oudets. Such devices shall be installed in 
accordance with the manufacturers' installation instructions. 

7.7.2 Cap AD Oudets. 

7.7.2.1 Each oudet, including a valve, shall be closed gastight 
with a threaded plug or cap immediately after installation and 
shall be left closed until the appliance or equipment is con- 
nected thereto. When an appliance or equipment is discon- 
nected from an outlet and the outlet is not to be used again 
immediately, it shall be capped or plugged gastight. 

Exception No. 1: Laboratory appliances installed in accordance with 
9. 6. 2(1) shall be permitted. 

Exception No. 2: The use of a listed quick-disconnect device with 
integral shutoffor listed gas convenience outlet shall be permitted. 

7.7.2.2 Appliance shutoff valves installed in fireplaces shall 
be removed and the piping capped gastight where the fire- 
place is used for solid fuel burning. 

7.8 Branch Pipe Connection. When a branch outlet is placed 
on a main supply line before it is known what size pipe will be 
connected to it, the outlet shall be of the same size as the line 
that supplies it. 

7.9 Manual Gas Shutoff Valves. (Also see 9.6.4.) 

7.9.1 Valves at Regulators. An accessible gas shutoff valve shall 
be provided upstream of each gas pressure regulator. Where two 
gas pressure regulators are installed in series in a single gas line, a 
manual valve shall not be required at the second regulator. 

7.9.2 Valves Controlling Multiple Systems. 

7.9.2.1 Accessibility of Gas Valves. Main gas shutoff valves 
controlling several gas piping systems shall be readily acces- 
sible for operation and installed so as to be protected from 
physical damage. They shall be marked with a metal tag or 
other permanent means attached by the installing agency so 



that the gas piping systems supplied through them can be 
readily identified. 

7.9.2.2 Shutoff Valves for Multiple House Lines. In multiple- 
tenant buildings supplied through a master meter, or through 
one service regulator where a meter is not provided, or where 
meters or service regulators are not readily accessible from the 
appliance or equipment location, an individual shutoff valve 
for each apartment or tenant line shall be provided at a con- 
venient point of general accessibility. In a common system 
serving a number of individual buildings, shutoff valves shall 
be installed at each building. 

7.9.2.3 Emergency Shutoff Valves. An exterior shutoff valve to 
permit turning off the gas supply to each building in an emer- 
gency shall be provided. The emergency shutoff valves shall be 
plainly marked as such and their locations posted as required 
by the authority having jurisdiction. 

7.10 Prohibited Devices. No device shall be placed inside the 
gas piping or fittings that will reduce the cross-sectional area or 
otherwise obstruct the free flow of gas, except where proper al- 
lowance in the piping system design has been made for such a 
device and where approved by the authority having jurisdiction. 

7.11 Systems Containing Gas-Air Mixtures Outside the Flam- 
mable Range. Where gas-air mixing machines are employed 
to produce mixtures above or below the flammable range, 
they shall be provided with stops to prevent adjustment of the 
mixture to within or approaching the flammable range. 

7.12 Systems Containing Flammable Gas-Air Mixtures. 

7.12.1 Required Components. A central premix system with a 
flammable mixture in the blower or compressor shall consist 
of the following components: 

( 1 ) Gas-mixing machine in the form of an automatic gas-air 
proportioning device combined with a downstream blower 
or compressor 

(2) Flammable mixture piping, minimum Schedule 40 NPS 

(3) Automatic firecheck(s) 

(4) Safety blowout(s) or backfire preventers for systems utiliz- 
ing flammable mixture lines above 2V£ in. nominal pipe 
size or the equivalent 

7. 1 2.2 Optional Components. The following components shall 
also be permitted to be utilized in any type central premix system: 

(1) Flowmeter(s) 

(2) Flame arrester(s) 

7.12.3 Additional Requirements. Gas-mixing machines shall 
have nonsparking blowers and shall be so constructed that a 
flashback will not rupture machine casings. 

7.12.4* Special Requirements for Mixing Blowers. A mixing 
blower system shall be limited to applications with minimum 
practical lengths of mixture piping, limited to a maximum 
mixture pressure of 10 in. w.c. (2.5 kPa) and limited to gases 
containing no more than 10 percent hydrogen. The blower 
shall be equipped with a gas-control valve at its air entrance so 
arranged that gas is admitted to the airstream, entering the 
blower in proper proportions for correct combustion by the 
type of burners employed, the said gas-control valve being of 
either the zero governor or mechanical ratio valve type that 
controls the gas and air adjustment simultaneously. No valves 
or other obstructions shall be installed between the blower 
discharge and the burner or burners. 



2006 Edition 



54-60 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-60 



7.12.5 Installation of Gas-Mixing Machines. 

7.12.5.1* Location. The gas-mixing machine shall be located 
in a large, well-ventilated area or in a small detached building 
or cutoff room provided with room construction and explo- 
sion vents in accordance with sound engineering principles. 
Such rooms or belowgrade installations shall have adequate 
positive ventilation. 

7.12.5.2 Electrical Requirements. Where gas-mixing machines 
are installed in well-ventilated areas, the type of electrical equip- 
ment shall be in accordance with NFPA 70, National Electrical Code, 
for general service conditions unless other hazards in the area 
prevail. Where gas-mixing machines are installed in small de- 
tached buildings or cutoff rooms, the electrical equipment and 
wiring shall be installed in accordance with NFPA 70 for hazard- 
ous locations (Articles 500 and 501, Class I, Division 2). 

7.12.5.3 Air Intakes. Air intakes for gas-mixing machines us- 
ing compressors or blowers shall be taken from outdoors 
whenever practical. 

7.12.5.4* Controls. Controls for gas-mixing machines shall in- 
clude interlocks and a safety shutoff valve of the manual reset 
type in the gas supply connection to each machine arranged 
to automatically shut off the gas supply in the event of high or 
low gas pressure. Except for open burner installations only, 
the controls shall be interlocked so that the blower or com- 
pressor will stop operating following a gas supply failure. 
Where a system employs pressurized air, means shall be pro- 
vided to shut off the gas supply in the event of air failure. 

7.12.5.5 Installation in Parallel. Centrifugal gas-mixing ma- 
chines in parallel shall be reviewed by the user and equipment 
manufacturer before installation, and means or plans for 
minimizing these effects of downstream pulsation and equip- 
ment overload shall be prepared and utilized as needed. 

7.12.6 Use of Automatic Firechecks, Safety Blowouts, or Back- 
fire Preventers. Automatic firechecks and safety blowouts or 
backfire preventers shall be provided in piping systems distrib- 
uting flammable air-gas mixtures from gas-mixing machines 
to protect the piping and the machines in the event of flash- 
back, in accordance with the following: 

(l)*Approved automatic firechecks shall be installed up- 
stream as close as practicable to the burner inlets follow- 
ing the firecheck manufacturers' instructions. 

(2) A separate manually operated gas valve shall be provided at 
each automatic firecheck for shutting off the flow of gas-air 
mixture through the firecheck after a flashback has oc- 
curred. The valve shall be located upstream as close as prac- 
tical to the inlet of the automatic firecheck. Caution: these 
valves shall not be reopened after a flashback has occurred 
until the firecheck has cooled sufficiently to prevent reigni- 
tion of the flammable mixture and has been reset properly. 

(3) Asafety blowout or backfiring preventer shall be provided in 
the mixture line near the outiet of each gas-mixing machine 
where the size of the piping is larger than V/z in. NPS, or 
equivalent, to protect the mixing equipment in the event of 
an explosion passing through an automatic firecheck. The 
manufacturers' instructions shall be followed when install- 
ing these devices, particularly after a disc has burst. The dis- 
charge from the safety blowout or backfire preventer shall 
be located or shielded so that particles from the ruptured 
disc cannot be directed toward personnel. Wherever there 
are interconnected installations of gas-mixing machines 
with safety blowouts or backfire preventers, provision shall 



be made to keep the mixture from other machines from 
reaching any ruptured disc opening. Check valves shall not 
be used for this purpose. 
(4) Large-capacity premix systems provided with explosion 
heads (rupture disc) to relieve excessive pressure in pipe- 
lines shall be located at and vented to a safe outdoor loca- 
tion. Provisions shall be provided for automatically shutting 
off the supply of the gas-air mixture in the event of rupture. 

7.13 Electrical Bonding and Grounding. 

7.13.1 Each aboveground portion of a gas piping system that 
is likely to become energized shall be electrically continuous 
and bonded to an effective ground-fault current path. Gas pip- 
ing shall be considered to be bonded when it is connected to 
appliances that are connected to the appliance grounding 
conductor of the circuit supplying that appliance. 

7.13.2 Gas piping shall not be used as a grounding conductor 
or electrode. 

7.14 Electrical Circuits. Electrical circuits shall not utilize gas 
piping or components as conductors. 

Exception: Low-voltage (50 V or less) control circuits, ignition cir- 
cuits, and electronic flame detection device circuits shall be permitted to 
make use of piping or components as a part of an electric circuit. 

7.15 Electrical Connections. 

7.15.1 All electrical connections between wiring and electri- 
cally operated control devices in a piping system shall conform 
to the requirements of NFPA 70, National Electrical Code. (See 
Section 7.13.) 

7.15.2 Any essential safety control depending on electric cur- 
rent as the operating medium shall be of a type that will shut 
off (fail safe) the flow of gas in the event of current failure. 



Chapter 8 Inspection, Testing, and Purging 

8.1 Pressure Testing and Inspection. 
8.1.1* General. 

8.1.1.1 Prior to acceptance and initial operation, all piping 
installations shall be inspected and pressure tested to deter- 
mine that the materials, design, fabrication, and installation 
practices comply with the requirements of this code. 

8.1.1.2 Inspection shall consist of visual examination, during 
or after manufacture, fabrication, assembly, or pressure tests 
as appropriate. Supplementary types of nondestructive inspec- 
tion techniques, such as magnetic-particle, radiographic, and 
ultrasonic, shall not be required unless specifically listed 
herein or in the engineering design. 

8.1.1.3 Where repairs or additions are made following the 
pressure test, the affected piping shall be tested. Minor repairs 
and additions are not required to be pressure tested, provided 
that the work is inspected and connections are tested with a 
noncorrosive leak-detecting fluid or other leak-detecting 
methods approved by the authority having jurisdiction. 

8.1.1.4 Where new branches are installed to new appli- 
ance (s), only the newly installed branch (es) shall be required 
to be pressure tested. Connections between the new piping 
and the existing piping shall be tested with a noncorrosive 
leak-detecting fluid or approved leak-detecting methods. 



2006 Edition 



ANSIZ223.1-61 



INSPECTION, TESTING, AND PURGING 



54-61 



8.1.1.5 Apiping system shall be tested as a complete unit or in 
sections. Under no circumstances shall a valve in a line be used 
as a bulkhead between gas in one section of the piping system 
and test medium in an adjacent section, unless two valves are 
installed in series with a valved "telltale" located between these 
valves. A valve shall not be subjected to the test pressure unless 
it can be determined that the valve, including the valve closing 
mechanism, is designed to safely withstand the pressure. 

8.1.1.6 Regulator and valve assemblies fabricated indepen- 
dently of the piping system in which they are to be installed 
shall be permitted to be tested with inert gas or air at the time 
of fabrication. 

8.1.2 Test Medium. The test medium shall be air, nitrogen, 
carbon dioxide, or an inert gas. 

OXYGEN SHALL NEVER BE USED. 

8.1.3 Test Preparation. 

8.1.3.1 Pipe joints, including welds, shall be left exposed for 
examination during the test. 

Exception: Covered or concealed pipe end joints that have been previ- 
ously tested in accordance with this code. 

8.1.3.2 Expansion joints shall be provided with temporary re- 
straints, if required, for the additional thrust load under test. 

8.1.3.3 Appliances and equipment that are not to be in- 
cluded in the test shall be either disconnected from the piping 
or isolated by blanks, blind flanges, or caps. Flanged joints at 
which blinds are inserted to blank off other equipment during 
the test shall not be required to be tested. 

8.1.3.4 Where the piping system is connected to appliances 
or equipment designed for operating pressures of less than 
the test pressure, such appliances or equipment shall be iso- 
lated from the piping system by disconnecting them and cap- 
ping the outlet(s) . 

8.1.3.5 Where the piping system is connected to appliances 
or equipment designed for operating pressures equal to or 
greater than the test pressure, such appliances or equipment 
shall be isolated from the piping system by closing the indi- 
vidual appliance or equipment shutoff valve (s). 

8.1.3.6 All testing of piping systems shall be done with due re- 
gard for the safety of employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist 
test pressures shall be installed if necessary. Prior to testing, the 
interior of the pipe shall be cleared of all foreign material. 

8.1.4 Test Pressure. 

8.1.4.1 Test pressure shall be measured with a manometer or 
with a pressure measuring device designed and calibrated to 
read, record, or indicate a pressure loss due to leakage during the 
pressure test period. The source of pressure shall be isolated be- 
fore the pressure tests are made. Mechanical gauges used to mea- 
sure test pressures shall have a range such that the highest end of 
the scale is not greater than 5 times the test pressure. 

8.1.4.2 The test pressure to be used shall be no less than 
IV2 times the proposed maximum working pressure, but not 
less than 3 psi (20 kPa), irrespective of design pressure. Where 
the test pressure exceeds 125 psi (862 kPa), the test pressure 
shall not exceed a value that produces a hoop stress in the 
piping greater than 50 percent of the specified minimum yield 
strength of the pipe. 



8.1.4.3* Test duration shall be not less than l A hour for each 
500 ft 3 (14 m 3 ) of pipe volume or fraction thereof. When test- 
ing a system having a volume less than 10 ft 3 (0.28 m 3 ) or a 
system in a single-family dwelling, the test duration shall be a 
minimum of 10 minutes. The duration of the test shall not be 
required to exceed 24 hours. 

8.1.5 Detection of Leaks and Defects. 

8.1.5.1 The piping system shall withstand the test pressure 
specified without showing any evidence of leakage or other de- 
fects. Any reduction of test pressures as indicated by pressure 
gauges shall be deemed to indicate the presence of a leak unless 
such reduction can be readily attributed to some other cause. 

8.1.5.2 The leakage shall be located by means of an approved 
gas detector, a noncorrosive leak detection fluid, or other ap- 
proved leak detection methods. Matches, candles, open 
flames, or other methods that provide a source of ignition 
shall not be used. 

8.1.5.3 Where leakage or other defects are located, the af- 
fected portion of the piping system shall be repaired or re- 
placed and retested. (See 8.1.1.3.) 

I 8.2 Piping System, Appliance, and Equipment Leakage Check. 

8.2.1 Test Gases. Leak checks using fuel gas shall be permit- 
ted in piping systems that have been pressure tested in accor- 
dance with Section 8.1. 

8.2.2 Before Turning Gas On. Before gas is introduced into a 
system of new gas piping, the entire system shall be inspected 
to determine that there are no open fittings or ends and that 
all valves at unused oudets are closed and plugged or capped. 

8.2.3* Leak Check. Immediately after the gas is turned on into a 
new system or into a system that has been initially restored after 
an interruption of service, the piping system shall be checked for 
leakage. Where leakage is indicated, the gas supply shall be shut 
off until the necessary repairs have been made. 

8.2.4 Placing Appliances and Equipment in Operation. Appli- 
ances and equipment shall not be placed in operation until 
after the piping system has been tested in accordance with 

8.2.3 and purged in accordance with 8.3.2. 

8.3* Purging. 

8.3.1 Removal from Service. When gas piping is to be opened 
for an addition, a modification, or service, the section to be 
worked on shall be turned off from the gas supply at the near- 
est convenient point and the line pressure vented to the out- 
doors or to ventilated areas of sufficient size to prevent accu- 
mulation of flammable mixtures. The remaining gas in this 
section of pipe shall be displaced with an inert gas as required 
by Table 8.3.1. 

8.3.2 Placing in Operation. When piping full of air is placed 
in operation, the air in the piping shall be displaced with fuel 
gas, except where such piping is required by Table 8.3.2 to be 
purged with an inert gas prior to introduction of fuel gas. The 
air can be safely displaced with fuel gas, provided that a mod- 
erately rapid and continuous flow of fuel gas is introduced at 
one end of the line and air is vented out at the other end. The 
fuel gas flow shall be continued without interruption until the 
vented gas is free of air. The point of discharge shall not be left 
unattended during purging. After purging, the vent shall then 
be closed. Where required by Table 8.3.2, the air in the piping 
shall first be displaced with an inert gas, and the inert gas shall 
then be displaced with fuel gas. 



2006 Edition 



54-62 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-62 



Table 8.3.1 Length of Piping Requiring 
Purging with Inert Gas for Servicing or 
Modification 



Nominal 
Pipe Size 

(in.) 



Length of Piping 
Requiring Purging 

(ft) 



Vh 


>50 


3 


>30 


4 


>15 


6 


>10 


8 or larger 


Any length 



For SI units, 1 ft = 0.305 m. 



Table 8.3.2 Length of Piping Requiring 
Purging with Inert Gas Before Being Placed in 
Operation 



Nominal 

Pipe Size 

(in.) 



Length of Piping 
Requiring Purging 

(ft) 



4 

6 

8 or larger 



>30 

>15 

>10 

Any length 



For SI units, 1 ft = 0.305 m. 



8.3.3 Discharge of Purged Gases. The open end of piping 
systems being purged shall not discharge into confined spaces 
or areas where there are sources of ignition unless precautions 
are taken to perform this operation in a safe manner by venti- 
lation of the space, control of purging rate, and elimination of 
all hazardous conditions. 

8.3.4 Placing Appliances and Equipment in Operation. After 
the piping system has been placed in operation, all appliances 
and equipment shall be purged and then placed in operation, 

as necessary. 



Chapter 9 Appliance, Equipment, and 
Accessory Installation 

9.1 General. 

9.1.1* Appliances, Equipment, and Accessories to Be Approved. 

Appliances, equipment, and accessories shall be approved. 

9.1.1.1 Approved shall mean "acceptable to the authority 
having jurisdiction." 

9.1.1.2 Listed appliances, equipment, and accessories shall 
be installed in accordance with Chapter 8 and the manufactur- 
er's installation instructions. 



9.1.1.3 Acceptance of unlisted appliances, equipment, and ac- 
cessories shall be on the basis of a sound engineering evaluation. 

9.1.1.4 The unlisted appliance, equipment, or accessory shall 
be safe and suitable for the proposed service and shall be rec- 
ommended for the service by the manufacturer. 



9.1.2 Added or Converted Appliances. When additional or re- 
placement appliances or equipment is installed or an appli- 
ance is converted to gas from another fuel, the location in 
which the appliances or equipment is to be operated shall be 
checked to verify the following: 

(1) Air for combustion and ventilation is provided where re- 
quired, in accordance with the provisions of Section 9.3. 
Where existing facilities are not adequate, they shall be 
upgraded to meet Section 9.3 specifications. 

(2) The installation components and appliances meet the clear- 
ances to combustible material provisions of 9.2.2. It shall be 
determined that the installation and operation of the addi- 
tional or replacement appliances do not render the remain- 
ing appliances unsafe for continued operation. 

(3) The venting system is constructed and sized in accor- 
dance with the provisions of Chapter 12. Where the exist- 
ing venting system is not adequate, it shall be upgraded to 
comply with Chapter 12. 

9.1.3 Type of Gas(es). It shall be determined whether the ap- 
pliance has been designed for use with the gas to which it will 
be connected. No attempt shall be made to convert the appli- 
ance from the gas specified on the rating plate for use with a 
different gas without consulting the installation instruction, 
the serving gas supplier, or the appliance manufacturer for 
complete instructions. 

9.1.4 Safety Shutoff Devices for Unlisted LP-Appliances 
Used Indoors. Unlisted appliances for use with undiluted liq- 
uefied petroleum gases and installed indoors, except attended 
laboratory equipment, shall be equipped with safety shutoff 
devices of the complete shutoff type. 

9.1.5 Use of Air or Oxygen Under Pressure. Where air or oxy- 
gen under pressure is used in connection with the gas supply, 
effective means such as a back-pressure regulator and relief 
valve shall be provided to prevent air or oxygen from passing 
back into the gas piping. Where oxygen is used, installation 
shall be in accordance with NFPA51, Standard for the Design and 
Installation of Oxygen-Fuel Gas Systems for Welding Cutting, and 
Allied Processes. 

9.1.6* Protection of Appliances from Fumes or Gases Other 
Than Products of Combustion. 

9.1.6.1 Where corrosive or flammable process fumes or gases 
are present, means for their safe disposal shall be provided. 
Such fumes or gases include carbon monoxide, hydrogen sul- 
fide, ammonia, chlorine, and halogenated hydrocarbons. 

9.1.6.2 Non-direct-vent type appliances installed in beauty 
shops, barber shops, or other facilities where chemicals that 
generate corrosive or flammable products such as aerosol 
sprays are routinely used shall be located in a mechanical 
room separate or partitioned off from other areas with provi- 
sions for combustion and dilution air from outdoors. Direct 
vent appliances shall be in accordance with the appliance 
manufacturer's installation instructions. 

9.1.7 Process Air. In addition to air needed for combustion in 
commercial or industrial processes, process air shall be provided 
as required for cooling of appliances, equipment, or material; for 
controlling dew point, heating, drying, oxidation, dilution, safety 
exhaust, odor control, air for compressors; and for comfort and 
proper working conditions for personnel. 



2006 Edition 



ANSI Z223. 1-63 



APPLIANCE, EQUIPMENT, AND ACCESSORY INSTALLATION 



54-63 



9.1.8 Building Structural Members. 

9.1.8.1 Structural members of a building shall not pass 
through appliances having an operating temperature in ex- 
cess of 500°F (260°C). 

9.1.8.2 Structural members passing through appliances having 
an operating temperature of 500°F (260°C) or less shall be of 
noncombustible material. Building columns, girders, beams, or 
trusses shall not be installed within appliances, unless insulation 
and ventilation are provided to avoid all deterioration in strength 
and linear expansion of the building structure in either a vertical 
or a horizontal direction. 

9.1.8.3 Appliances and equipment shall be furnished either 
with load distributing bases or with a sufficient number of sup- 
ports to prevent damage to either the building structure or 
appliance and equipment. 

9.1.8.4 At the locations selected for installation of appliances 
and equipment, the dynamic and static load-carrying capaci- 
ties of the building structure shall be checked to determine 
whether they are adequate to carry the additional loads. The 
appliances and equipment shall be supported and shall be 
connected to the piping so as not to exert undue stress on the 
connections. 

9.1.9 Flammable Vapors. Appliances shall not be installed in 
areas where the open use, handling, or dispensing of flam- 
mable liquids occurs, unless the design, operation, or installa- 
tion reduces the potential of ignition of the flammable vapors. 
Appliances installed in compliance with 9.1.10 through 9.1.12 
shall be considered to comply with the intent of this provision. 

9.1.10 Installation in Residential Garages. 

9.1.10.1 Appliances in residential garages and in adjacent 
spaces that open to the garage and are not part of the living 
space of a dwelling unit shall be installed so that all burners 
and burner ignition devices are located not less than 18 in. 
(460 mm) above the floor unless listed as flammable vapor 
ignition resistant. 

9.1.10.2 Such appliances shall be located or protected so they 
are not subject to physical damage by a moving vehicle. 

9.1.10.3 Where appliances are installed in a separate, en- 
closed space having access only from outside of the garage, 
such appliances shall be permitted to be installed at floor 
level, providing the required combustion air is taken from the 
exterior of the garage. 

9.1.11 Installation in Commercial Garages. 

9.1.11.1 Parking Structures. Appliances installed in enclosed, 
basement, and underground parking structures shall be installed 
in accordance with NFPA88A, Standard for Parking Structures. 

9.1.11.2 Repair Garages. Appliances installed in repair ga- 
rages shall be installed in a detached building or room, sepa- 
rated from repair areas by walls or partitions, floors, or floor 
ceiling assemblies that are constructed so as to prohibit the 
transmission of vapors and having a fire resistance rating of 
not less than 1 hour, and that have no openings in the wall 
separating the repair area within 8 ft (2.4 m) of the floor. Wall 
penetrations shall be firestopped. Air for combustion pur- 
poses shall be obtained from the outdoors. The heating room 
shall not be used for the storage of combustible materials. 

Exception No. 1: Overhead heaters where installed not less than 8 ft 
(2. 4 m) above the floor shall be permitted. 



Exception No. 2: Heating appliances for vehicle repair areas where 
there is no dispensing or transferring of Class I or Class II flammable 
or combustible liquids or liquefied petroleum gas shall be installed in 
accordance with NFPA30A, Code for Motor Fuel Dispensing Facilities 
and Repair Garages. 

9.1.12 Installation in Aircraft Hangars. Heaters in aircraft 
hangars shall be installed in accordance with NFPA 409, Stan- 
dard on Aircraft Hangars. 

9.1.13 Appliance Physical Protection. Where it is necessary to 
locate appliances close to a passageway traveled by vehicles or 
machinery, guardrails or bumper plates shall be installed to 
protect the equipment from damage. 

9.1.14 Venting of Flue Gases. Appliances shall be vented in 
accordance with the provisions of Chapter 12. 

9.1.15 Extra Device or Attachment. No device or attachment 
shall be installed on any appliance that could in any way im- 
pair the combustion of gas. 

9.1.16 Adequate Capacity of Piping. When additional appli- 
ances are being connected to a gas piping system, the existing 
piping shall be checked to determine whether it has adequate 
capacity. (See Section 5. 4. ) Where inadequate, the existing sys- 
tem shall be enlarged as necessary, or separate gas piping of 
adequate capacity shall be run from the point of delivery to 
the appliance. 

9.1.17 Avoiding Strain on Gas Piping. Appliances shall be so 
supported and so connected to the piping as not to exert un- 
due strain on the connections. 

9.1.18 Gas Appliance Pressure Regulators. Where the gas sup- 
ply pressure is higher than that at which the appliance is de- 
signed to operate or varies beyond the design pressure limits 
of the appliance, a gas appliance pressure regulator shall be 
installed. 

9. 1 . 19 Venting of Gas Appliance Pressure Regulators. Venting 
of gas appliance pressure regulators shall comply with the fol- 
lowing requirements: 

( 1 ) Appliance pressure regulators requiring access to the atmo- 
sphere for successful operation shall be equipped with vent 
piping leading outdoors or, if the regulator vent is an inte- 
gral part of the appliance, into the combustion chamber ad- 
jacent to a continuous pilot, unless constructed or equipped 
with a vent-limiting means to limit the escape of gas from the 
vent opening in the event of diaphragm failure. 

(2) Vent-limiting means shall be employed on listed appli- 
ance pressure regulators only. 

(3) In the case of vents leading outdoors, means shall be em- 
ployed to prevent water from entering this piping and also to 
prevent blockage of vents by insects and foreign matter. 

(4) Under no circumstances shall a regulator be vented to the 
appliance flue or exhaust system. 

(5) In the case of vents entering the combustion chamber, 
the vent shall be located so the escaping gas will be readily 
ignited by the pilot and the heat liberated thereby will not 
adversely affect the normal operation of the safety shutoff 
system. The terminus of the vent shall be securely held in 
a fixed position relative to the pilot. For manufactured 
gas, the need for a flame arrester in the vent piping shall 
be determined. 

(6) A vent line(s) from an appliance pressure regulator and a 
bleed line(s) from a diaphragm-type valve shall not be con- 
nected to a common manifold terminating in a combustion 
chamber. Vent lines shall not terminate in positive-pressure- 
type combustion chambers. 



2006 Edition 



54-64 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-64 



9.1.20 Bleed Lines for Diaphragm-Type Valves. Bleed lines 
shall comply with the following requirements: 

(1) Diaphragm-type valves shall be equipped to convey bleed 
gas to the outdoors or into the combustion chamber adja- 
cent to a continuous pilot. 

(2) In the case of bleed lines leading outdoors, means shall be 
employed to prevent water from entering this piping and 
also to prevent blockage of vents by insects and foreign 
matter. 

(3) Bleed lines shall not terminate in the appliance flue or 
exhaust system. 

(4) In the case of bleed lines entering the combustion cham- 
ber, the bleed line shall be located so the bleed gas will be 
readily ignited by the pilot and the heat liberated thereby 
will not adversely affect the normal operation of the safety 
shutoff system. The terminus of the bleed line shall be 
securely held in a fixed position relative to the pilot. For 
manufactured gas, the need for a flame arrester in the 
bleed line piping shall be determined. 

(5) A bleed line(s) from a diaphragm-type valve and a vent 
line(s) from an appliance pressure regulator shall not be 
connected to a common manifold terminating in a combus- 
tion chamber. Bleed lines shall not terminate in positive- 
pressure-type combustion chambers. 

9.1.21 Combination of Appliances and Equipment. Any com- 
bination of appliances, equipment, attachments, or devices 
used together in any manner shall comply with the standards 
that apply to the individual appliance and equipment. 

9.1.22 Installation Instructions. The installing agency shall 
conform to the appliance and equipment manufacturers' rec- 
ommendations in completing an installation. The installing 
agency shall leave the manufacturers' installation, operating, 
and maintenance instructions in a location on the premises 
where they will be readily available for reference and guidance 
of the authority having jurisdiction, service personnel, and the 
owner or operator. 

9.1.23 Protection of Outdoor Appliances. Appliances not 
listed for outdoor installation but installed outdoors shall be 
provided with protection to the degree that the environment 
requires. Appliances listed for outdoor installation shall be 
permitted to be installed without protection in accordance 
with the manufacturer's installation instructions. (See 9.2.1.) 

9.2 Accessibility and Clearance. 

9.2.1 Accessibility for Service. All appliances shall be located 
with respect to building construction and other equipment so 
as to permit access to the appliance. Sufficient clearance shall 
be maintained to permit cleaning of heating surfaces; the re- 
placement of filters, blowers, motors, burners, controls, and 
vent connections; the lubrication of moving parts where nec- 
essary; the adjustment and cleaning of burners and pilots; and 
the proper functioning of explosion vents, if provided. For 
attic installation, the passageway and servicing area adjacent to 
the appliance shall be floored. 

9.2.2 Clearance to Combustible Materials. Appliances and 
their vent connectors shall be installed with clearances 
from combustible material so their operation will not create 
a hazard to persons or property. Minimum clearances be- 
tween combustible walls and the back and sides of various 



conventional types of appliances and their vent connectors 
are specified in Chapters 10 and 12. (Reference can also be 
made to NFF A 211, Standard for Chimneys, Fireplaces, Vents, and 
Solid Fuel-Burning Appliances. ) 

9.2.3 Installation on Carpeting. Appliances shall not be in- 
stalled on carpeting, unless the appliances are listed for such 
installation. 

9.3* Air for Combustion and Ventilation. 

9.3.1 General. 

9.3.1.1 Air for combustion, ventilation, and dilution of flue 
gases for appliances installed in buildings shall be obtained by 
application of one of the methods covered in 9.3.2 through 
9.3.6. Where the requirements of 9.3.2 are not met, outdoor 
air shall be introduced in accordance with methods covered in 
9.3.3 through 9.3.6. 

Exception No. 1: This provision shall not apply to direct vent 
appliances. 

Exception No. 2: Type 1 clothes dryers that are provided with makeup 
air in accordance with 10.4.3. 

9.3.1.2 Appliances of other than natural draft design and 
other than Category I vented appliances shall be provided 
with combustion, ventilation, and dilution air in accordance 
with the appliance manufacturer's instructions. 

9.3.1.3 Appliances shall be located so as not to interfere with 
proper circulation of combustion, ventilation, and dilution air. 

9.3.1.4 Where used, a draft hood or a barometric draft regu- 
lator shall be installed in the same room or enclosure as the 
appliance served so as to prevent any difference in pressure 
between the hood or regulator and the combustion air supply. 

9.3.1.5 Makeup air requirements for the operation of ex- 
haust fans, kitchen ventilation systems, clothes dryers, and 
fireplaces shall be considered in determining the adequacy of 
a space to provide combustion air requirements. 

9.3.2 Indoor Combustion Air. The required volume of indoor 
air shall be determined in accordance with the method in 
9.3.2.1 or 9.3.2.2 except that where the air infiltration rate is 
known to be less than 0.40 ACH, the method in 9.3.2.2 shall be 
used. The total required volume shall be the sum of the re- 
quired volume calculated for all appliances located within the 
space. Rooms communicating directly with the space in which 
the appliances are installed through openings not furnished 
with doors, and through combustion air openings sized and 
located in accordance with 9.3.2.3, are considered a part of 
the required volume. 

9.3.2.1* Standard Method. The minimum required volume 
shall be 50 ft 3 per 1000 Btu/hour (4.8 m 3 /kW). 

9.3.2.2* Known Air Infiltration Rate Method. Where the air 
infiltration rate of a structure is known, the minimum re- 
quired volume shall be determined as follows: 

( 1 ) For appliances other than fan-assisted, calculate using the 
following equation: 



Required Volume ol 



ACH 1^1000 Btu/hr 



2006 Edition 



ANSIZ223.1-65 



APPLIANCE, EQUIPMENT, AND ACCESSORY INSTALLATION 



54-65 



(2) For fan-assisted appliances, calculate using the following 
equation: 



Required Volume , 



15 ft 3 



ACH 



'/«* 



1000 Btu/hr 



where: 

htker = all appliances other than fan-assisted input in 

Btu per hour 
Ij- an = fan-assisted appliance input in Btu per hour 
ACH = air change per hour (percent of volume of space 

exchanged per hour, expressed as a decimal) 

(3) For purposes of this calculation, an infiltration rate 
greater than 0.60 ACH shall not be used in the equa- 
tions in 9.3.2.2(1) and 9.3.2.2(2). 

9.3.2.3 Indoor Opening Size and Location. Openings used to 
connect indoor spaces shall be sized and located in accor- 
dance with the following: 

(\)* Combining spaces on the same story. Each opening shall have a 
minimum free area of 1 in. 2 /1000 Btu/hr (2200 mm 2 /kW) 
of the total input rating of all appliances in the space but not 
less than 100 in. 2 (0.06 m 2 ) . One opening shall commence 
within 12 in. (300 mm) of the top, and one opening shall 
commence within 12 in. (300 mm) of the bottom, of the 
enclosure [see Figure A.9.3.2.3(l)]. The minimum dimension 
of air openings shall be not less than 3 in. (80 mm). 

(2) Combining spaces in different stories. The volumes of spaces 
in different stories shall be considered as communicating 
spaces where such spaces are connected by one or more 
openings in doors or floors having a total minimum free 
area of 2 in. 2 /1000 Btu/hr (4400 mm 2 /kW) of total input 
rating of all appliances. 

9.3.3 Outdoor Combustion Air. Outdoor combustion air shall 
be provided through opening(s) to the outdoors in accor- 
dance with the methods in 9.3.3.1 or 9.3.3.2. The minimum 
dimension of air openings shall not be less than 3 in. (80 mm) . 

9.3.3.1 Two Permanent Openings Method. Two permanent 
openings, one commencing within 12 in. (300 mm) of the top 
and one commencing within 12 in. (300 mm) of the bottom, 
of the enclosure shall be provided. The openings shall com- 
municate directly, or by ducts, with the outdoors or spaces that 
freely communicate with the outdoors, as follows: 

(l)*Where direcdy communicating with the outdoors or 
where communicating to the outdoors through vertical 
ducts, each opening shall have a minimum free area of 
1 in. 2 /4000 Btu/hr (550 mm 2 /kW) of total input rating of 
all appliances in the enclosure. [See Figure A. 9.3.3. 1(1 )(a) and 
Figure A.9.3.3.1(l)(b).] 

(2) *Where communicating with the outdoors through horizon- 
tal ducts, each opening shall have a minimum free area of 
1 in. 2 /2000 Btu/hr (1100 mm 2 /kW) of total input rating of 
all appliances in the enclosure. [See Figure A.9.3.3. 1(2).] 

9.3.3.2* One Permanent Opening Method. One permanent 
opening, commencing within 12 in. (300 mm) of the top of the 
enclosure, shall be provided. The appliance shall have clearances 
of at least 1 in. (25 mm) from the sides and back and 6 in. 
(150 mm) from the front of the appliance. The opening shall 
direcdy communicate with the outdoors or shall communicate 
through a vertical or horizontal duct to the outdoors or spaces 
that freely communicate with the outdoors (see Figure A.9.3.3. 2) 
and shall have a minimum free area of die following: 



(1)1 in. 73000 Btu/hr (700 mm 2 per kW) of the total input 
rating of all appliances located in the enclosure, and 

(2) Not less than the sum of the areas of all vent connectors in 
the space 

9.3.4 Combination Indoor and Outdoor Combustion Air. The 

use of a combination of indoor and outdoor combustion air 
shall be in accordance with (1) through (3) (see example calcu- 
lation in Annex J): 

( 1 ) Indoor Openings. Where used, openings connecting the in- 
terior spaces shall comply with 9.3.2.3. 

(2) Outdoor Opening(s) Location. Outdoor opening(s) shall be 
located in accordance with 9.3.3. 

(3) Outdoor Opening(s) Size. The outdoor opening(s) size shall 
be calculated in accordance with the following: 

(a) The ratio of the interior spaces shall be the available 
volume of all communicating spaces divided by the 
required volume. 

(b) The outdoor size reduction factor shall be 1 minus 
the ratio of interior spaces. 

(c) The minimum size of outdoor opening(s) shall be 
the full size of outdoor opening(s) calculated in ac- 
cordance with 9.3.3, multiplied by the reduction fac- 
tor. The minimum dimension of air openings shall 
not be less than 3 in. (80 mm). 

9.3.5 Engineered Installations. Engineered combustion air in- 
stallations shall provide an adequate supply of combustion, 
ventilation, and dilution air and shall be approved by the au- 
thority having jurisdiction. 

9.3.6 Mechanical Combustion Air Supply. Where all combus- 
tion air is provided by a mechanical air supply system, the com- 
bustion air shall be supplied from outdoors at the minimum rate 
of 0.35 ftVmin per 1000 Btu/hr (0.034 m 3 /min per kW) for all 
appliances located within the space. 

9.3.6.1 Where exhaust fans are installed, additional air shall 
be provided to replace the exhausted air. 

9.3.6.2 Each of the appliances served shall be interlocked to the 
mechanical air supply system to prevent main burner operation 
where the mechanical air supply system is not in operation. 

9.3.6.3 Where combustion air is provided by the building's 
mechanical ventilation system, the system shall provide the 
specified combustion air rate in addition to the required ven- 
tilation air. 

9.3.7 Louvers, Grilles, and Screens. , 

9.3.7.1 Louvers and Grilles. The required size of openings for 
combustion, ventilation, and dilution air shall be based on the 
net free area of each opening. Where the free area through a 
design of louver or grille or screen is known, it shall be used in 
calculating the size opening required to provide the free area 
specified. Where the louver and grille design and free area are 
not known, it shall be assumed that wood louvers will have 
25 percent free area, and metal louvers and grilles will have 
75 percent free area. Nonmotorized louvers and grilles shall 
be fixed in the open position. 

9.3.7.2 Minimum Screen Mesh Size. Screens shall not be 
smaller than l A in. mesh. 

9.3.7.3 Motorized Louvers. Motorized louvers shall be inter- 
locked with the appliance so they are proven in the full open 
position prior to main burner ignition and during main 
burner operation. Means shall be provided to prevent the 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSI Z223. 1-66 



main burner from igniting should the louver fail to open dur- 
ing burner startup and to shut down the main burner if the 
louvers close during burner operation. 

9.3.8 Combustion Air Ducts. Combustion air ducts shall com- 
ply with 9.3.8.1 through 9.3.8.8. 

9.3.8.1 Ducts shall be constructed of galvanized steel or a 
material having equivalent corrosion resistance, strength, and 
rigidity. 

Exception: Within dwellings units, unobstructed stud and joist 
spaces shall not be prohibited from conveying combustion air, provided 
that not more than onejireblock is removed. 

9.3.8.2 Ducts shall terminate in an unobstructed space, allow- 
ing free movement of combustion air to the appliances. 

9.3.8.3 Ducts shall serve a single space. 

9.3.8.4 Ducts shall not serve both upper and lower combustion 
air openings where both such openings are used. The separation 
between ducts serving upper and lower combustion air openings 
shall be maintained to the source of combustion air. 

9.3.8.5 Ducts shall not be screened where terminating in an 
attic space. 

9.3.8.6 Horizontal upper combustion air ducts shall not 
slope downward toward the source of combustion air. 

9.3.8.7 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry, metal, or factory built chimney shall not be used to 
supply combustion air. 

Exception: Direct vent appliances designed for installation in a solid 
fuel-burning fireplace where installed in accordance with the manufac- 
turer's installation instructions. 

9.3.8.8 Combustion air intake openings located on the exte- 
rior of the building shall have the lowest side of the combus- 
tion air intake openings located at least 12 in. (300 mm) verti- 
cally from the adjoining grade level. 

9.4 Appliances on Roofs. 

9.4.1 General. 

9.4.1.1 Appliances on roofs shall be designed or enclosed so 
as to withstand climatic conditions in the area in which they 
are installed. Where enclosures are provided, each enclosure 
shall permit easy entry and movement, shall be of reasonable 
height, and shall have at least a 30 in. (760 mm) clearance 
between the entire service access panel(s) of the appliance 
and the wall of the enclosure. 

9.4.1.2 Roofs on which appliances are to be installed shall be 
capable of supporting the additional load or shall be rein- 
forced to support the additional load. 

9.4.1.3 All access locks, screws, and bolts shall be of corrosion- 
resistant material. 

9.4.2 Installation of Appliances on Roofs. 

9.4.2.1 Appliances shall be installed in accordance with the 
manufacturer's installation instructions. 

9.4.2.2 Appliances shall be installed on a well-drained surface 
of the roof. At least 6 ft (1.8 m) of clearance shall be available 
between any part of the appliance and the edge of a roof or 
similar hazard, or rigidly fixed rails, guards, parapets, or other 



building structures at least 42 in. (1.1 m) in height shall be 
provided on the exposed side. 

9.4.2.3 All appliances requiring an external source of electri- 
cal power for its operation shall be provided with (1) a readily 
accessible electrical disconnecting means within sight of the 
appliance that will completely deenergize the appliance, and 
(2) a 120 V ac grounding-type receptacle outlet on the roof 
adjacent to the appliance. The receptacle outlet shall be on 
the supply side of the disconnect switch. 

9.4.2.4 Where water stands on the roof at the appliance or in 
the passageways to the appliance, or where the roof is of a 
design having a water seal, a suitable platform, walkway, or 
both shall be provided above the water line. Such platform (s) 
or walkway(s) shall be located adjacent to the appliance and 
control panels so that the appliance can be safely serviced 
where water stands on the roof. 

9.4.3 Access to Appliances on Roofs. 

9.4.3.1 Appliances located on roofs or other elevated loca- 
tions shall be accessible. 

9.4.3.2 Buildings of more than 15 ft (4.6 m) in height shall 
have an inside means of access to the roof, unless other means 
acceptable to the authority having jurisdiction are used. 

9.4.3.3 The inside means of access shall be a permanent or 
foldaway inside stairway or ladder, terminating in an enclo- 
sure, scuttle, or trapdoor. Such scuttles or trapdoors shall be at 
least 22 in. x 24 in. (560 mm x 610 mm) in size, shall open 
easily and safely under all conditions, especially snow, and 
shall be constructed so as to permit access from the roof side 
unless deliberately locked on the inside. At least 6 ft (1.8 m) of 
clearance shall be available between the access opening and 
the edge of the roof or similar hazard, or rigidly fixed rails or 
guards a minimum of 42 in. (1.1 m) in height shall be pro- 
vided on the exposed side. Where parapets or other building 
structures are utilized in lieu of guards or rails, they shall be a 
minimum of 42 in. (1.1 m) in height. 

9.4.3.4 Permanent lighting shall be provided at the roof ac- 
cess. The switch for such lighting shall be located inside the 
building near the access means leading to the roof. 

9.4.4 Additional Provisions. (Also see 9.1.23, 9.2.1, and 12.4.3.) 
9.5 Appliances in Attics. 

9.5.1 Attic Access. An attic in which an appliance is installed 
shall be accessible through an opening and passageway at least 
as large as the largest component of the appliance, and not 
less than 22 in. x 30 in. (560 mm x 760 mm). 

9.5.1.1 Where the height of the passageway is less than 6 ft 
(1.8 m), the distance from the passageway access to the appli- 
ance shall not exceed 20 ft (6.1 m) measured along the cen- 
terline of the passageway. 

9.5.1.2 The passageway shall be unobstructed and shall have 
solid flooring not less than 24 in. (610 mm) wide from the 
entrance opening to the appliance. 

9.5.2 Work Platform. A level working platform not less than 
30 in. (760 mm) by 30 in. shall be provided in front of the 
service side of the appliance. 

9.5.3 Lighting and Convenience Outlet. A permanent 120 V 
receptacle outiet and a lighting fixture shall be installed near 
the appliance. The switch controlling the lighting fixture shall 
be located at the entrance to the passageway. 



2006 Edition 



ANSI Z223.1-67 



APPLIANCE, EQUIPMENT, AND ACCESSORY INSTALLATION 



54-67 



9.6 Appliance and Equipment Connections to Building Piping. 

9.6.1 Connecting Appliances and Equipment. Appliances and 
equipment shall be connected to the building piping in com- 
pliance with 9.6.4 through 9.6.6 by one of the following: 

(1) Rigid metallic pipe and fittings. 

(2) Semirigid metallic tubing and metallic fittings. Aluminum 
alloy tubing shall not be used in exterior locations. 

(3) Alisted connector in compliance with ANSI Z21 .24, Standard 
for Connectors far Gas Appliances. The connector shall be used 
in accordance with the manufacturer's installation instruc- 
tions and shall be in the same room as the appliance. Only 
one connector shall be used per appliance. 

(4) Alisted connector in compliance with ANSI Z21.75, Con- 
nectors for Outdoor Gas Appliances and Manufactured Homes. 
Only one connector shall be used per appliance. 

(5) CSST where installed in accordance with the manufactur- 
er's installation instructions. 

(6) Listed nonmetallic gas hose connectors in accordance with 
9.6.2. 

(7) In 9.6.1(2), 9.6.1(3), 9.6.1(4), 9.6.1(5), and 9.6.1(6), the 
connector or tubing shall be installed so as to be pro- 
tected against physical and thermal damage. Aluminum 
alloy tubing and connectors shall be coated to protect 
against external corrosion where they are in contact with 
masonry, plaster, or insulation or are subject to repeated 
wettings by such liquids as water (except rain water) , de- 
tergents, or sewage. 

(8) Materials addressed in 9.6.1(2), 9.6.1(3), 9.6.1(4), 9.6.1(5), 
and 9.6.1 (6) shall not be installed through an opening in an 
appliance housing, cabinet, or casing, unless the tubing or 
connector is protected against damage. 

9.6.1.1 Commercial Cooking Appliances. Commercial cook- 
ing appliances that are moved for cleaning and sanitation pur- 
poses shall be connected in accordance with the connector 
manufacturer's installation instructions using a listed appli- 
ance connector complying with ANSI Z21.69, Connectors for 
Movable Gas Appliances. 

9.6.2 Use of Nonmetallic Gas Hose Connectors. Listed gas 
hose connectors shall be used in accordance with the manu- 
facturer's installation instructions and as follows: 

(1) Indoor. Indoor gas hose connectors shall be used only to 
connect laboratory, shop, and ironing appliances requir- 
ing mobility during operation. 

(a) An appliance shutoff valve shall be installed where 
the connector is attached to the building piping. 

(b) The connector shall be of minimum length and shall 
not exceed 6 ft (1.8m). 

(c) The connector shall not be concealed and shall not 
extend from one room to another or pass through 
wall partitions, ceilings, or floors. 

(2) Outdoor. Outdoor gas hose connectors are permitted to 
connect portable outdoor appliances. 

(a) An appliance shutoff valve, a listed quick-disconnect 
device, or a listed gas convenience outlet shall be in- 
stalled where the connector is attached to the supply 
piping and in such a manner so as to prevent the 
accumulation of water or foreign matter. 

(b) This connection shall be made only in the outdoor 
area where the appliance is to be used. 

9.6.3 Connection of Portable and Mobile Industrial Appliances. 

9.6.3.1 Where portable industrial appliances or appliances 
requiring mobility or subject to vibration are connected to the 



building gas piping system by the use of a flexible hose, the 
hose shall be suitable and safe for the conditions under which 
it can be used. 

9.6.3.2 Where industrial appliances requiring mobility are 
connected to the rigid piping by the use of swivel joints or 
couplings, the swivel joints or couplings shall be suitable for 
the service required and only the minimum number required 
shall be installed. 

9.6.3.3 Where industrial appliances subject to vibration are 
connected to the building piping system by the use of all metal 
flexible connectors, the connectors shall be suitable for the 
service required. 

9.6.3.4 Where flexible connections are used, they shall be of 
the minimum practical length and shall not extend from one 
room to another or pass through any walls, partitions, ceilings, 
or floors. Flexible connections shall not be used in any con- 
cealed location. They shall be protected against physical or 
thermal damage and shall be provided with gas shutoff valves 
in readily accessible locations in rigid piping upstream from 
the flexible connections. 

9.6.4 Appliance Shutoff Valves and Connections. Each appli- 
ance connected to a piping system shall have an accessible, 
approved manual shutoff valve with a nondisplaceable valve 
member, or a listed gas convenience outlet. Appliance shutoff 
valves and convenience outlets shall serve a single appliance 
only and shall be installed in accordance with 9.6.4.1. 

9.6.4.1 The shutoff valve shall be located within 6 ft (1.8 m) 
of the appliance it serves except as permitted in 9.6.4.2 or 
9.6.4.3. 

(1) Where a connector is used, the valve shall be installed 
upstream of the connector. A union or flanged connec- 
tion shall be provided downstream from the valve to per- 
mit removal of appliance controls. 

(2) Shutoff valves serving decorative appliances shall be per- 
mitted to be installed in fireplaces if listed for such use. 

9.6.4.2 Shutoff valves serving appliances installed in vented 
fireplaces and ventless firebox enclosures shall not be re- 
quired to be located within 6 ft ( 1 .8 m) of the appliance where 
such valves are readily accessible and permanently identified. 
The piping from the shutoff valve to within 6 ft (1.8 m) of the 
appliance shall be designed, sized and installed in accordance 
with Chapters 5, 6, and 7. 

9.6.4.3 Where installed at a manifold, the appliance shutoff 
valve shall be located within 50 ft (15 m) of the appliance 
served and shall be readily accessible and permanently identi- 
fied. The piping from the manifold to within 6 ft of the appli- 
ance shall be designed, sized and installed in accordance with 
Chapters 5, 6, and 7. 

9.6.5 Quick-Disconnect Devices. 

9.6.5.1 Quick-disconnect devices used to connect appliances 
to the building piping shall be listed to ANSI Z21.41/CSA6.9, 
Quick-Disconnect Devices for Use with Gas Fuel Appliances. 

9.6.5.2 Where installed indoors, an approved manual shutoff 
valve with a nondisplaceable valve member shall be installed 
upstream of the quick-disconnect device. 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSI Z223. 1-68 



9.6.6* Gas Convenience Outlets. Appliances shall be permit- 
ted to be connected to the building piping by means of a listed 
gas convenience outlet, in conjunction with a listed appliance 
connector, used in accordance with the manufacturer's instal- 
lation instructions. 

9.6.7 Sediment Trap. Where a sediment trap is not incorpo- 
rated as a part of the appliance, a sediment trap shall be installed 
as close to the inlet of the appliance as practicable at the time of 
appliance installation. The sediment trap shall be either a tee 
fitting with a capped nipple in the bottom outlet as illustrated in 
Figure 9.6.7 or other device recognized as an effective sediment 
trap. Illuminating appliances, ranges, clothes dryers, decorative 
appliances for installation in vented fireplaces, gas fireplaces, and 
outdoor grills shall not be required to be so equipped. 



Gas supply inlet 



Q 



To 

equipment • 
inlet 



-Tee fitting 



Nipple 
Cap-K 



t 

3 in. (80 mm) 

minimum 

L 



^ 



~T 



FIGURE 9.6.7 Method of Installing a Tee Fitting Sediment 
Trap. 

9.6.8 Installation of Piping. Piping shall be installed in a man- 
ner not to interfere with inspection, maintenance, or servicing 
of the appliances. 

9.7 Electrical. 

9.7.1 Electrical Connections. Electrical connections between 
appliances and the building wiring, including the grounding 
of the appliances, shall conform to NFPA70, National Electrical 
Code. 

9.7.2 Electrical Ignition and Control Devices. Electrical igni- 
tion, burner control, and electrical vent damper devices shall 
not permit unsafe operation of the appliance in the event of 
electrical power interruption or when the power is restored. 

9.7.3 Electrical Circuit. The electrical circuit employed for 
operating the automatic main gas-control valve, automatic pi- 
lot, room temperature thermostat, limit control, or other elec- 
trical devices used with the appliances shall be in accordance 
with the wiring diagrams certified or approved by the original 
appliance manufacturer. 

9.7.4 Continuous Power. All appliances using electrical con- 
trols shall have the controls connected into a permanently live 
electrical circuit — that is, one that is not controlled by a light 
switch. Central heating appliances shall be provided with a 
separate electrical circuit. 

9.8 Room Temperature Thermostats. 

9.8.1 Locations. Room temperature thermostats shall be in- 
stalled in accordance with the manufacturer's instructions. 



9.8.2 Drafts. Any hole in the plaster or panel through which 
the wires pass from the thermostat to the appliance being con- 
trolled shall be sealed so as to prevent drafts from affecting the 
thermostat. 



Chapter 10 Installation of Specific Appliances 

10.1 General. 

10.1.1 Application. This chapter is applicable primarily to 
nonindustrial-type appliances and installations and, unless 
specifically indicated, does not apply to industrial appliances 
and installations. Listed appliances shall be installed in accor- 
dance with the manufacturer's installation instructions, or as 
elsewhere specified in this chapter as applicable to the appli- 
ance. Unlisted appliances shall be installed as specified in this 
chapter as applicable to the appliances. For additional infor- 
mation concerning particular gas appliances and accessories, 
including industrial types, reference can be made to the stan- 
dards listed in Chapter 2 and Annex L. 

10.1.2* Installation in a Bedroom or Bathroom. Appliances 
shall not be installed so their combustion, ventilation, and di- 
lution air are obtained only from a bedroom or bathroom 
unless the bedroom or bathroom has the required volume in 
accordance with 9.3.2. 

10.1.3 Room Size in Comparison Calculation. Where the 
room size in comparison with the size of the appliance is to be 
calculated, the total volume of the appliance is determined 
from exterior dimensions and is to include fan compartments 
and burner vestibules, where used. Where the actual ceiling 
height of a room is greater than 8 ft (2.4 m), the volume of the 
room is figured on the basis of a ceiling height of 8 ft (2.4 m). 

10.2 Air-Conditioning Appliances (Gas-Fired Air Conditioners 
and Heat Pumps). 

10.2.1 Independent Gas Piping. Gas piping serving heating 
appliances shall be permitted to also serve cooling appliances 
where heating and cooling appliances cannot be operated si- 
multaneously. (See Section 5.4.) 

10.2.2 Connection of Gas Engine-Powered Air Conditioners. 

To protect against the effects of normal vibration in service, gas 
engines shall not be rigidly connected to the gas supply piping. 

10.2.3 Clearances for Indoor Installation. The installation of 
air-conditioning appliances shall comply with the following 
requirements: 

(1) Listed air-conditioning appliances installed in a room 
large in comparison with size of appliance shall be in- 
stalled with clearances in accordance with the manufac- 
turer's instructions. [See Table 10.2.3(a) and 3.3.88, Room 
Large in Comparison with Size of Equipment] 

(2) Air-conditioning appliances installed in rooms that are 
NOT large (such as alcoves and closets) in comparison 
with the size of the appliance shall be listed for such instal- 
lations and installed in accordance with the manufactur- 
er's instructions. Listed clearances shall not be reduced 
by the protection methods described in Table 10.2.3(b), 
regardless of whether the enclosure is of combustible or 
noncombustible material. 



2006 Edition 



ANSI Z223. 1-69 



INSTALLATION OF SPECIFIC APPLIANCES 



54-69 



(3) Unlisted air-conditioning appliances shall be installed with 
clearances from combustible material of not less than 18 in. 
(460 mm) above the appliance and at the sides, front, and 
rear and 9 in. (230 mm) from the draft hood. 

(4) Air-conditioning appliances (listed and unlisted) in- 
stalled in rooms that are large in comparison with the size 
of the appliance shall be permitted to be installed with 
reduced clearances to combustible material, provided the 
combustible material or appliance is protected as de- 
scribed in Table 10.2.3(b) [see 10.2.3(2)]. 

(5) Where the furnace plenum is adjacent to plaster on metal 
lath or noncombustible material attached to combustible 
material, the clearance shall be measured to the surface 
of the plaster or other noncombustible finish where the 
clearance specified is 2 in. (50 mm) or less. 

(6) Listed air-conditioning appliances shall have the clear- 
ance from supply ducts within 3 ft (0.9 m) of the furnace 
plenum be not less than that specified from the furnace 
plenum. No clearance is necessary beyond this distance. 

10.2.4 Assembly and Installation. Air-conditioning appliances 
shall be installed in accordance with the manufacturer's in- 
structions. Unless the appliance is listed for installation on a 
combustible surface such as a floor or roof, or unless the sur- 
face is protected in an approved manner, it shall be installed 
on a surface of noncombustible construction with noncom- 
bustible material and surface finish and with no combustible 
material against the underside thereof. 

10.2.5 Furnace Plenums and Air Ducts. A furnace plenum 
supplied as a part of the air-conditioning appliance shall be 
installed in accordance with the manufacturer's instructions. 
Where a furnace plenum is not supplied with the appliance, 
any fabrication and installation instructions provided by the 
manufacturer shall be followed. The method of connecting 
supply and return ducts shall facilitate proper circulation of 
air. Where the air conditioner is installed within a room not 
large in comparison with the size of the appliance, the air 
circulated by the appliance shall be handled by ducts that are 



sealed to the casing of the appliance and that separate the 
circulating air from the combustion and ventilation air. 

10.2.6* Refrigeration Coils. (See 10.3.7 and 10.3.8.) 

10.2.7 Switches in Electrical Supply Line. Means for inter- 
rupting the electrical supply to the air-conditioning appliance 
and to its associated cooling tower (if supplied and installed in 
a location remote from the air conditioner) shall be provided 
within sight of and not over 50 ft (15 m) from the air condi- 
tioner and cooling tower. 

10.3 Central Heating Boilers and Furnaces. 

10.3.1 Location. Central heating furnace and low-pressure 
boiler installations in bedrooms or bathrooms shall comply 
with one of the following: 

( 1 ) Central heating furnaces and low-pressure boilers shall be 
installed in a closet located in the bedroom or bathroom, 
the closet shall have a weather-stripped solid door with a 
self-closing device, and all combustion air shall be ob- 
tained from the outdoors. 

(2) Central heating furnaces and low-pressure boilers shall be 
of the direct vent type. 

10.3.2 Clearance. 

10.3.2.1 Listed central heating furnaces and low-pressure 
boilers installed in a room large in comparison with the size of 
the appliance shall be installed with clearances in accordance 
with the manufacturer's instructions. (See 3.3.88, Room Large in 
Comparison with Size of Equipment.) 

10.3.2.2 Central heating furnaces and low-pressure boilers in- 
stalled in rooms that are NOT large (such as alcoves and closets) 
in comparison with the size of the appliance shall be listed for 
such installations. Listed clearances shall not be reduced by the 
protection methods described in Table 10.2.3(b) and illustrated 
in Figure 10.3.2.2(a) through Figure 10.3.2.2(c), regardless of 
whether the enclosure is of combustible or noncombustible 
material. 



Table 10.2.3(a) Clearances to Combustible Material for Unlisted Furnaces, 
Boilers, and Air Conditioners Installed in Rooms That Are Large in Comparison 
with the Size of Appliances 

Minimum Clearance (in.) 



Appliance 


Above and Sides 

of Furnace 

Plenum 


Top of Boiler 


Jacket Sides 
and Rear 


Front 


Draft Hood 
and Barometric 
Draft Regulator 


Single-Wall 
Vent Connector 


I Automatically fired, forced air or 
gravity system, equipped with 
temperature limit control that cannot 
be set higher than 250°F (121°C) 


6 




6 


18 


6 


18 


II Automatically fired heating boilers — 
steam boilers operating at not over 
15 psi (103 kPa) and hot water boilers 
operating at 250"F (121°C) or less 


6 


6 


6 


18 


18 


18 


III Central heating boilers and furnaces, 
other than in I or II 


18 


18 


18 


18 


18 


18 


IV Air-conditioning appliances 


18 


18 


18 


18 


18 


18 



Note: See 10.2.3 for additional requirements for air-conditioning appliances and 10.3.1 for additional re- 
quirements for centra] heating boilers and furnaces. 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSI Z223. 1-70 



Table 10.2.3(b) Reduction of Clearances with Specified Forms of Protection 












Where the required clearance with no protection from appliance 
or single-wall metal pipe is: 


vent connector, 






36 in. 


18 in. 


12 in. 


9 in. 


6 


in. 


Type of protection applied to 


Allowable Clearances with Specified Protection (in.) 


and covering all surfaces of 
combustible material within the 
distance specified as the required 
clearance with no protection [See 
Figure 10.3.2.2(a) through Figure 
10.3.2.2(c).] 


Use Col. 


1 for clearances above appliance or horizontal connector. Use Col. 2 for clearances from 
vertical connector, and single-wall metal pipe. 


appliance, 


Above 
Col. 1 


Sides and 
Rear 
Col. 2 


Sides and 
Above Rear 
Col. 1 Col. 2 


Sides and 
Above Rear 
Col. 1 Col. 2 


Sides and 
Above Rear 
Col. 1 Col. 2 


Above 
Col. 1 


Sides and 
Rear 
Col. 2 


(1) 3V2 in. thick masonry wall 
without ventilated air space 


— 


24 


— 12 


— 9 


— 


6 


— 


5 


(2) Vi in. insulation board over 
1 in. glass fiber or 
mineral wool batts 


24 


18 


12 9 


9 6 


6 


5 


4 


3 


(3) 0.024 in. (nominal 24 gauge) 
sheet metal over 1 in. glass 
fiber or mineral wool batts 
reinforced with wire on rear 
face with ventilated air space 


18 


12 


9 6 


6 4 


5 


3 


3 


3 


(4) 3M> in. thick masonry wall 
with ventilated air space 


— 


12 


— 6 


— 6 


— 


6 


— 


6 


(5) 0.024 in. (nominal 24 gauge) 
sheet metal with ventilated air 
space 

(6) 14 in. thick insulation board 
with ventilated air space 


18 

18 


12 
12 


9 6 

9 6 


6 4 
6 4 


5 

5 


3 
3 


3 
3 


2 
3 


(7) 0.024 in. (nominal 24 gauge) 
sheet metal with ventilated air 
space over 0.024 in. (nominal 
24 gauge) sheet metal with 
ventilated air space 

(8) 1 in. glass fiber or mineral 
wool batts sandwiched between 
two sheets 0.024 in. (nominal 
24 gauge) sheet metal with 
ventilated air space 


18 

18 


12 
12 


9 6 
9 6 


6 4 
6 4 


5 

5 


3 
3 


3 

3 


3 
3 



For SI units, 1 in. = 25.4 mm. 
Notes: 

( 1 ) Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood 
clearance and relief, and accessibility of servicing. 

(2) All clearances shall be measured from the outer surface of the combustible material to the nearest point on 
the surface of the appliance, disregarding any intervening protection applied to the combustible material. 

(3) Spacers and ties shall be of noncombustible material. No spacer or tie shall be used direcdy opposite the 
appliance or connector. 

(4) Where all clearance reduction systems use a ventilated air space, adequate provision for air circulation 
shall be provided as described. [See Figure 10.3.2.2(b) andFigure 10.3.2.2(c).] 

(5) There shall be at least 1 in. (25 mm) between clearance reduction systems and combustible walls and 
ceilings for reduction systems using a ventilated air space. 

(6) Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum 1 in. 
(25 mm) air gap. To provide adequate air circulation, the bottom and top edges, or only the side and top 
edges, or all edges shall be left open. 

(7) Mineral wool batts (blanket or board) shall have a minimum density of 8 lb/ft 3 (128 kg/m 3 ) and a 
minimum melting point of 1500T (816°C). 

(8) Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 
Btu in./ft 2 /hr-°F (0.144 W/m-K) or less. 

(9) There shall be at least 1 in. (25 mm) between the appliance and the protector. In no case shall the clearance 
between the appliance and the combustible surface be reduced below that allowed in Table 10.2.3(b). 

(10) All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable. 

(11) Listed single-wall connectors shall be installed in accordance with the manufacturer's installation in- 
structions. 



2006 Edition 



ANSI Z223. 1-71 



INSTALLATION OF SPECIFIC APPLIANCES 



54-71 



Construction using combustible - 
material, plastered or unplastered 



X 



X. 



X 



X 



X 



i: 



T 

A 



I out 



Sheet metal or 




JL other protection 

/ \« — Gas equipment 

I J or vent connector 



Notes: 

A equals the clearance with no protection specified in Tables 10.2.3(a) 
and 12.5.1 and in the sections applying to various types of equipment. 
B equals the reduced clearance permitted in accordance with 
Table 10.2.3(b). The protection applied to the construction using 
combustible material shall extend far enough in each direction to 
make C equal to A. 

FIGURE 10.3.2.2(a) Extent of Protection Necessary to Reduce 
Clearances from Gas Appliance or Vent Connectors. 



10.3.2.3 Unlisted central heating furnaces and low-pressure 
boilers installed in rooms that are large in comparison with 
the size of the appliance shall be installed with clearances not 
less than those specified in Table 10.2.3(a). 

10.3.2.4 Central heating furnaces and low-pressure boilers 
(listed and unlisted) installed in rooms that are large in com- 
parison with the size of the appliance shall be permitted to be 
installed with reduced clearances to combustible material pro- 
vided the combustible material or appliance is protected as 
described in Table 10.2.3(b) (see 10.3.2). 

10.3.2.5 Front clearance shall be sufficient for servicing the 
burner and the furnace or boiler. 

10.3.2.6 Where the furnace plenum is adjacent to plaster on 
metal lath or noncombustible material attached to combus- 
tible material, the clearance shall be measured to the surface 
of the plaster or other noncombustible finish where the clear- 
ance specified is 2 in. (50 mm) or less. 

10.3.2.7 The clearances to these appliances shall not inter- 
fere with combustion air, draft hood clearance and relief, and 
accessibility for servicing. (See 9.2. 1, Section 9.3, and 12. 13. 7.) 

10.3.2.8 Listed central heating furnaces shall have the clear- 
ance from supply ducts within 3 ft (0.9 m) of the furnace ple- 
num be not less than that specified from the furnace plenum. 
No clearance is necessary beyond this distance. 

10.3.2.9 Unlisted central heating furnaces with temperature 
limit controls that cannot be set higher than 250°F (121°C) 
shall have the clearance from supply ducts within 6 ft (1.8 m) 
of the furnace plenum be not less than 6 in. (150 mm). No 
clearance is necessary beyond this distance. 

10.3.2.10 Central heating furnaces other than those listed in 
10.3.2.8 or 10.3.2.9 shall have clearances from the supply ducts 
of not less than 18 in. (460 mm) from the furnace plenum for 
the first 3 ft (0.9 m), then 6 in. (150 mm) for the next 3 ft 
(0.9 m), and 1 in. (25 mm) beyond 6 ft (1.8 m). 

10.3.3 Assembly and Installation. A central heating boiler or 
furnace shall be installed in accordance with the manufacturer's 
instructions and shall be installed on a floor of noncombustible 
construction with noncombustible flooring and surface finish 




Wall protector mounted 
with all edges open 





Mounted with side 
and top edges open 



Mounted with top 
and bottom edges 
open 



Wall protector mounted 
on single flat wall 



Must be mounted with top 
and bottom edges open 



Wall protector installed in corner 



VI II 

Combustible 
wall 




- Nail or screw anchor 



< Clearance 

reduction system 



1 in. (25 mm) noncombustible 
spacer such as stacked washers, 
small-diameter pipe, tubing, or 
electrical conduit. 



Masonry walls can be attached to combustible walls using wall ties. 
Spacers should not be used directly behind appliance or connector. 



FIGURE 10.3.2.2(b) 
System. 



Wall Protector Clearance Reduction 



and with no combustible material against the underside thereof, 
or on fire-resistive slabs or arches having no combustible material 
against the underside thereof. 



Exception No. 
floor. 



1: Appliances listed for installation on a combustible 
Installation on a floor protected in an approved 



Exception No. 2. 
manner. 

10.3.4 Temperature- or Pressure-Limiting Devices. Steam and 
hot water boilers, respectively, shall be provided with approved 
automatic limiting devices for shutting down the burner(s) to 
prevent boiler steam pressure or boiler water temperature from 
exceeding the maximum allowable working pressure or tempera- 
ture. Safety limit controls shall not be used as operating controls. 

10.3.5 Low Water Cutoff. Hot water boilers installed above the 
radiation level and all steam boilers shall be provided with an 
automatic means to shut off the fuel supply to the burner(s) if the 
boiler water level drops to the lowest safe water line. 



2006 Edition 



54-72 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-72 



Combustible wall 




1 in. (25 mm) >* 

minimum air space 
between masonry 
and combustible wall 



4 in. (100 mm) 
nominal brick wall 



Bottom and top course 
of bricks staggered for 
ventilation 



A strip of heavy-gauge steel 
used for added support 

Note: Do not place masonry wall ties directly 
behind appliance or connector. 



Corrugated 
metal wall 
ties 




Masonry wall tie 



FIGURE 10.3.2.2(c) Masonry Clearance Reduction System. 



10.3.6* Steam Safety and Pressure Relief Valves. Steam and 
hot water boilers shall be equipped, respectively, with listed or 
approved steam safety or pressure relief valves of appropriate 
discharge capacity and conforming with ASME requirements. 
Ashutoff valve shall not be placed between the relief valve and 
the boiler or on discharge pipes between such valves and the 
atmosphere. 



(1) A refrigeration coil shall not be installed in conjunction 
with a forced air furnace where circulation of cooled air is 
provided by the furnace blower, unless the blower has suf- 
ficient capacity to overcome the external static resistance 
imposed by the duct system and cooling coil and the air 
throughput necessary for heating or cooling, whichever is 
greater. 

(2) Furnaces shall not be located upstream from cooling 
units, unless the cooling unit is designed or equipped so 
as not to develop excessive temperature or pressure. 

(3) Refrigeration coils shall be installed in parallel with or on 
the downstream side of central furnaces to avoid conden- 
sation in the heating element, unless the furnace has 
been specifically listed for downstream installation. With a 
parallel flow arrangement, the dampers or other means 
used to control flow of air shall be sufficiently tight to 
prevent any circulation of cooled air through the furnace. 

(4) Means shall be provided for disposal of condensate and to 
prevent dripping of condensate on the heating element. 

10.3.9 Cooling Units Used with Heating Boilers. 

10.3.9.1 Boilers, where used in conjunction with refrigera- 
tion systems, shall be installed so that the chilled medium is 
piped in parallel with the heating boiler with appropriate 
valves to prevent the chilled medium from entering the heat- 
ing boiler. 

10.3.9.2 Where hot water heating boilers are connected to 
heating coils located in air-handling units where they can be 
exposed to refrigerated air circulation, such boiler piping sys- 
tems shall be equipped with flow control valves or other auto- 
matic means to prevent gravity circulation of the boiler water 
during the cooling cycle. 



10.3.6.1 

floor. 



Relief valves shall be piped to discharge near the 10.4 Clothes Dryers. 



10.3.6.2 The entire discharged piping shall be at least the 
same size as the relief valve discharge piping. 

10.3.6.3 Discharge piping shall not contain threaded end 
connection at its termination point. 

10.3.7 Furnace Plenums and Air Ducts. 

10.3.7.1 Furnace plenums and air ducts shall be installed in 
accordance with NFPA 90A, Standard for the Installation ofAir- 
Conditioning and Ventilating Systems, or NFPA 90B, Standard for 
the Installation of Warm Air Heating and Air-Conditioning Systems. 

10.3.7.2 A furnace plenum supplied as a part of a furnace 
shall be installed in accordance with the manufacturer's in- 
structions. 

10.3.7.3* Where a furnace plenum is not supplied with the 
furnace, any fabrication and installation instructions provided 
by the manufacturer shall be followed. The method of con- 
necting supply and return ducts shall facilitate proper circula- 
tion of air. 

10.3.7.4 Where a furnace is installed so supply ducts carry air 
circulated by the furnace to areas outside the space containing 
the furnace, the return air shall also be handled by a duct(s) 
sealed to the furnace casing and terminating outside the space 
containing the furnace. 

10.3.8 Refrigeration Coils. The installation of refrigeration 
coils shall comply with the following requirements: 



10.4.1 Clearance. The installation of clothes dryers shall com- 
ply with the following requirements: 

(1) Listed Type 1 clothes dryers shall be installed with a mini- 
mum clearance of 6 in. (150 mm) from adjacent combus- 
tible material. Clothes dryers listed for installation at re- 
duced clearances shall be installed in accordance with the 
manufacturer's installation instructions. Type 1 clothes 
dryers installed in closets shall be specifically listed for 
such installation. 

(2) Listed Type 2 clothes dryers shall be installed with clear- 
ances of not less than shown on the marking plate and in 
the manufacturer's instructions. Type 2 clothes dryers de- 
signed and marked "For use only in noncombustible loca- 
tions" shall not be installed elsewhere. 

(3) Unlisted clothes dryers shall be installed with clearances 
to combustible material of not less than 18 in. (460 mm). 
Combustible floors under unlisted clothes dryers shall be 
protected in an approved manner. 

10.4.2 Exhausting to the Outdoors. Type 1 and Type 2 clothes 
dryers shall be exhausted to the outdoors. 

10.4.3 Provisions for Make-Up Air. 

10.4.3.1 Make-up air shall be provided for Type 1 clothes 
dryers in accordance with the manufacturers' installation in- 
structions. 

10.4.3.2 Provision for make-up air shall be provided for 
Type 2 clothes dryers, with a minimum free area (see 9.3.5) of 
1 in.VlOOO Btu/hr (2200 mm 2 /kW) total input rating of the 
dryer(s) installed. 



2006 Edition 



ANSI Z223. 1-73 



INSTALLATION OF SPECIFIC APPLIANCES 



54-73 



10.4.4 Exhaust Ducts for Type 1 Clothes Dryers. 

10.4.4.1 A clothes dryer exhaust duct shall not be connected 
into any vent connector, gas vent, chimney, crawl space, attic, 
or other similar concealed space. 

10.4.4.2 Ducts for exhausting clothes dryers shall not be as- 
sembled with screws or other fastening means that extend into 
the duct and that would catch lint and reduce the efficiency of 
the exhaust system. 

10.4.4.3 Exhaust ducts shall be constructed of rigid metallic 
material. Transition ducts used to connect the dryer to the 
exhaust duct shall be listed for that application or installed in 
accordance with the clothes dryer manufacturer's installation 
instructions. 

10.4.5 Exhaust Ducts for Type 2 Clothes Dryers. 

10.4.5. 1 Exhaust ducts for Type 2 clothes dryers shall comply 
with 10.4.4. 

10.4.5.2 Exhaust ducts for Type 2 clothes dryers shall be con- 
structed of sheet metal or other noncombustible material. 
Such ducts shall be equivalent in strength and corrosion resis- 
tance to ducts made of galvanized sheet steel not less than 
0.0195 in. (0.5 mm) thick. 

10.4.5.3 Type 2 clothes dryers shall be equipped or installed 
with lint-controlling means. 

10.4.5.4 Exhaust ducts for unlisted Type 2 clothes dryers shall 
be installed with a minimum clearance of 6 in. (150 mm) from 
adjacent combustible material. Where exhaust ducts for Type 2 
clothes dryers are installed with reduced clearances, the adjacent 
combustible material shall be protected in accordance with 
Table 10.2.3(b). 

10.4.5.5 Where ducts pass through walls, floors, or partitions, 
the space around the duct shall be sealed with noncombus- 
tible material. 

10.4.5.6 Multiple installations of Type 2 clothes dryers shall 
be made in a manner to prevent adverse operation due to 
back pressures that might be created in the exhaust systems. 

10.4.6 Multiple-Family or Public Use. All clothes dryers in- 
stalled for multiple-family or public use shall be equipped with 
approved safety shutoff devices and shall be installed as speci- 
fied for a Type 2 clothes dryer under 10.4.5. 

10.5 Conversion Burners. Installation of conversion burners 
shall conform to ANSI Z21.8, Installation of Domestic Gas Conver- 
sion Burners. 

10.6 Decorative Appliances for Installation in Vented Fireplaces. 

10.6.1* Prohibited Installations. Decorative appliances for in- 
stallation in vented fireplaces shall not be installed in bath- 
rooms or bedrooms unless the appliance is listed and the bed- 
room or bathroom has the required volume in accordance 
with 9.3.2. 

10.6.2 Installation. A decorative appliance for installation in a 
vented fireplace shall be installed only in a vented fireplace 
having a working chimney flue and constructed of noncom- 
bustible materials. These appliances shall not be thermostati- 
cally controlled. 

10.6.2.1 A listed decorative appliance for installation in a 
vented fireplace shall be installed in accordance with the 
manufacturer's installation instructions. 



10.6.2.2 A decorative appliance for installation in a vented 
fireplace, where installed in a manufactured home, shall be 
listed for installation in manufactured homes. 

10.6.2.3 An unlisted decorative appliance for installation in a 
vented Fireplace shall be installed in a fireplace having a per- 
manent free opening, based on appliance input rating and 
chimney height equal to or greater than that specified in 
Table 10.6.2.3. 

10.6.3 Fireplace Screens. A fireplace screen shall be installed 
with a decorative appliance for installation in a vented fireplace. 

10.7 Gas Fireplaces, Vented. 

10.7.1* Prohibited Installations. Vented gas fireplaces shall 
not be installed in bathrooms or bedrooms unless the appli- 
ance is listed and the bedroom or bathroom has the required 
volume in accordance with 9.3.2. 

Exception: Direct-vent gas fireplaces. 

10.7.2 Installation. The installation of vented gas fireplaces 
shall comply with the following requirements: 

(1) Listed vented gas fireplaces shall be installed in accor- 
dance with the manufacturer's installation instructions 
and where installed in or attached to combustible mate- 
rial shall be specifically listed for such installation. 

(2) Unlisted vented gas fireplaces shall not be installed in or 
attached to combustible material and shall also comply 
with the following: 

(a) They shall have a clearance at the sides and rear of 
not less than 18 in. (460 mm). 

(b) Combustible floors under unlisted vented gas fire- 
places shall be protected in an approved manner. 

(c) Unlisted appliances of other than the direct vent type 
shall be equipped with a draft hood and shall be 
properly vented in accordance with Chapter 12. 

(d) Appliances that use metal, asbestos, or ceramic material 
to direct radiation to the front of the appliance shall 
have a clearance of 36 in. (910 mm) in front and, if 
constructed with a double back of metal or ceramic, 
shall be installed with a minimum clearance of 18 in. 
(460 mm) at the sides and 12 in. (300 mm) at the rear. 

(3) Panels, grilles, and access doors that are required to be 
removed for normal servicing operations shall not be at- 
tached to the building. 

(4) Direct-vent gas fireplaces shall be installed with the vent- 
air intake terminal in the outdoors and in accordance 
with the manufacturers' instructions. 

10.7.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 9.3. 

10.8 Non-Recirculating Direct Gas-Fired Industrial Air Heaters. 

10.8.1 Application. Direct gas-fired industrial air heaters of 
the non-recirculating type shall be listed in accordance with 
ANSI Z83.4/CSA 3.7, Non-Recirculating Direct Gas-Fired Indus- 
trial Air Heaters. 

10.8.2 Prohibited Installations. 

10.8.2.1 Non-recirculating direct gas-fired industrial air heat- 
ers shall not serve any area containing sleeping quarters. 



2006 Edition 



54-74 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-74 



Table 10.6.2.3 Free Opening Area of Chimney Damper for Venting Flue Gases from Unlisted 
Decorative Appliances for Installation in Vented Fireplaces 





Minimum Permanent Free Opening (in. 2 )* 


Chimney 
Height 


8 


13 


20 


29 


39 


51 


64 












(ft) 






Appliance Input Rating (Btu/hr) 






6 


7,800 


14,000 


23,200 


34,000 


46,400 


62,400 


80,000 


8 


8,400 


15,200 


25,200 


37,000 


50,400 


68,000 


86,000 


10 


9,000 


16,800 


27,600 


40,400 


55,800 


74,400 


96,400 


15 


9,800 


18,200 


30,200 


44,600 


62,400 


84,000 


108,800 


20 


10,600 


20,200 


32,600 


50,400 


68,400 


94,000 


122,200 


30 


11,200 


21,600 


36,600 


55,200 


76,800 


105,800 


138,600 



For SI units, 1 ft = 0.305 m; 1 in. 2 = 645 mm 2 ; 1000 Btu/hr = 0.293 kW. 

* The first six minimum permanent free openings (8 in. 2 to 51 in. 2 ) correspond approximately to the 
cross-sectional areas of chimneys having diameters of 3 in. through 8 in., respectively. The 64 in. 2 opening 
corresponds to the cross-sectional area of standard 8 in. x 8 in. chimney tile. 



10.8.2.2 Non-recirculating direct gas-fired industrial air heat- 
ers shall not recirculate room air. 

10.8.3 Installation. 

10.8.3.1 Non-recirculating direct gas-fired industrial air heat- 
ers shall be installed in accordance with the manufacturer's 
instructions. 

10.8.3.2 Non-recirculating direct gas-fired industrial air heaters 
shall be installed only in industrial or commercial occupancies. 

10.8.3.3 Non-recirculating direct gas-fired industrial air heat- 
ers shall be permitted to provide fresh air ventilation. 

1 0.8.3.4 Non-recirculating direct gas-fired industrial air heaters 
shall be provided with access for removal of burners; replace- 
ment of motors, controls, filters and other working parts; and for 
adjustment and lubrication of parts requiring maintenance. 

10.8.4 Clearance from Combustible Materials. Non- 
recirculating direct gas-fired industrial air heaters shall be in- 
stalled with a clearance from combustible materials of not less 
than that shown on the rating plate and the manufacturer's 
instructions. 

10.8.5 Air Supply. All air to the non-recirculating direct gas- 
fired industrial air heater shall be ducted directly from out- 
doors. Where outdoor air dampers or closing louvers are used, 
they shall be verified to be in the open position prior to main 
burner operation. 

10.8.6 Atmospheric Vents or Gas Reliefs or Bleeds. Non- 
recirculating direct gas-fired industrial air heaters with valve 
train components equipped with atmospheric vents, gas re- 
liefs, or bleeds shall have their vent lines, gas reliefs, or bleeds 
lead to a safe point outdoors. Means shall be employed on 
these lines to prevent water from entering and to prevent 
blockage from insects and foreign matter. An atmospheric 
vent line shall not be required to be provided on a valve train 
component equipped with a listed vent limiter. 

10.8.7 Relief Openings. The design of the installation shall 
include adequate provisions to permit the non-recirculating 
direct gas-fired industrial air heater to operate at its rated air- 
flow without overpressurizing the space served by the heater 
by taking into account the structure's designed infiltration 



rate, properly designed relief openings, or an interlocked 
powered exhaust system, or a combination of these methods. 

10.8.7.1 The structure's designed infiltration rate and the 
size of relief opening(s) shall be determined by approved en- 
gineering methods. 

10.8.7.2 Louver or counterbalanced gravity damper relief 
openings shall be permitted. Where motorized dampers or 
closeable louvers are used, they shall be proved to be in their 
open position prior to main burner operation. 

10.8.8 Purging. Inlet ducting, when used, shall be purged 
with at least four air changes prior to an ignition attempt. 

10.9 Recirculating Direct Gas-Fired Industrial Air Heaters. 

10.9.1 Application. Direct gas-fired industrial air heaters of 
the recirculating type shall be listed in accordance with ANSI 
Z83.18, Recirculating Direct Gas-Fired Industrial Air Heaters. 

10.9.2 Prohibited Installations. 

10.9.2.1 Recirculating direct gas-fired industrial air heaters 
shall not serve any area containing sleeping quarters. 

10.9.2.2* Recirculating direct gas-fired industrial air heaters 
shall not recirculate room air in buildings that contain flam- 
mable solids, liquids, or gases, explosive materials, or sub- 
stances that can become toxic when exposed to flame or heat. 

10.9.3 Installation. Installation of direct gas-fired industrial 
air heaters shall comply with the following requirements: 

(1) Recirculating direct gas-fired industrial air heaters shall 
be installed in accordance with the manufacturer's in- 
structions. 

(2) Recirculating direct gas-fired industrial air heaters shall 
be installed only in industrial or commercial occupancies. 

10.9.4 Clearance from Combustible Materials. Recirculating 
direct gas-fired industrial air heaters shall be installed with a 
clearance from combustible materials of not less than that shown 
on the rating plate and the manufacturer's instructions. 

10.9.5 Air Supply. Ventilation air to the recirculating direct 
gas-fired industrial air heater shall be ducted directly from 
outdoors. Air to the recirculating direct gas-fired industrial air 



2006 Edition 



ANSI Z223.1-75 



INSTALLATION OF SPECIFIC APPLIANCES 



54-75 



heater in excess of the minimum ventilation air specified on 
the heater's rating plate shall be taken from the building, 
ducted direcdy from outdoors, or a combination of both. 
Where outdoor air dampers or closing louvers are used, they 
shall be verified to be in the open position prior to main 
burner operation. 

10.9.6 Atmospheric Vents, Gas Reliefs, or Bleeds. Recirculat- 
ing direct gas-fired industrial air heaters with valve train com- 
ponents equipped with atmospheric vents, gas reliefs, or 
bleeds shall have their vent lines, gas reliefs, or bleeds lead to a 
safe point outdoors. Means shall be employed on these lines to 
prevent water from entering and to prevent blockage from 
insects and foreign matter. An atmospheric vent line shall not 
be required to be provided on a valve train component 
equipped with a listed vent limiter. 

10.9.7 Relief Openings. The design of the installation shall 
include adequate provisions to permit the recirculating direct 
gas-fired industrial air heater to operate at its rated airflow 
without overpressurizing the space served by the heater, by 
taking into account the structure's designed infiltration rate, 
properly designed relief openings, an interlocked powered ex- 
haust system, or a combination of these methods. 

10.9.7.1 The structure's designed infiltration rate and the 
size of relief opening(s) shall be determined by approved en- 
gineering methods. 

10.9.7.2 Louver or counterbalanced gravity damper relief 
openings shall be permitted. Where motorized dampers or 
closeable louvers are used, they shall be proved to be in their 
open position prior to main burner operation. 

10.9.8 Purging. Inlet ducting, when used, shall be purged 
with at least four air changes prior to an ignition attempt. 

10.10 Duct Furnaces. 

10.10.1 Clearances. The installation of duct furnaces shall 
comply with the following clearance requirements: 

(1) Listed duct furnaces shall be installed with clearances of 
at least 6 in. (150 mm) between adjacent walls, ceilings, 
and floors of combustible material and the furnace draft 
hood and shall comply with the following: 

(a) Furnaces listed for installation at lesser clearances 
shall be installed in accordance with the manufactur- 
er's installation instructions. 

(b) In no case shall the clearance be such as to interfere 
with combustion air and accessibility. (See 9.2.1 and 
Section 9.3.) 

(2) Unlisted duct furnaces shall be installed with clear- 
ances to combustible material in accordance with the 
clearances specified for unlisted furnaces and boilers 
in Table 10.2.3(a). Combustible floors under unlisted 
duct furnaces shall be protected in an approved 
manner. 

10.10.2 Erection of Appliances. Duct furnaces shall be erected 
and firmly supported in accordance with the manufacturers' in- 
structions. 

10.10.3 Access Panels. The ducts connected to duct furnaces 
shall have removable access panels on both the upstream and 
downstream sides of the furnace. 

10.10.4 Location of Draft Hood and Controls. The controls, 
combustion air inlet, and draft hoods for duct furnaces shall 



be located outside the ducts. The draft hood shall be located 
in the same enclosure from which combustion air is taken. 

10.10.5 Circulating Air. Where a duct furnace is installed so 
that supply ducts carry air circulated by the furnace to areas 
outside the space containing the furnace, the return air shall 
also be handled by a duct(s) sealed to the furnace casing and 
terminating outside the space containing the furnace. The 
duct furnace shall be installed on the positive-pressure side of 
the circulating air blower. 

10.10.6 Duct Furnaces Used with Refrigeration Systems. 

10.10.6.1 A duct furnace shall not be installed in conjunction 
with a refrigeration coil where circulation of cooled air is pro- 
vided by the blower. 

Exception: Where the blower has sufficient capacity to overcome the 
external static resistance imposed by the duct system, furnace, and the 
cooling coil and the air throughput necessary for healing or cooling, 
whichever is greater. 

10.10.6.2 Duct furnaces used in conjunction with cooling ap- 
pliances shall be installed in parallel with or on the upstream 
side of cooling coils to avoid condensation within heating ele- 
ments. With a parallel flow arrangement, the dampers or 
other means used to control the flow of air shall be sufficiently 
tight to prevent any circulation of cooled air through the unit. 

Exception: Where the duct furnace has been specifically listed for 
downstream installation. 

10.10.6.3 Where ductfumaces are to be located upstream from 
cooling units, the cooling unit shall be so designed or equipped 
as to not develop excessive temperatures or pressures. 

10. 10.6.4 Where a duct furnace is installed downstream of an 
evaporative cooler or air washer, the heat exchanger shall be 
constructed of corrosion-resistant materials. Stainless steel, 
ceramic-coated steel, and an aluminum-coated steel in which 
the bond between the steel and the aluminum is an iron- 
aluminum alloy are considered to be corrosion resistant. Air 
washers operating with chilled water that deliver air below the 
dew point of the ambient air at the duct furnace are consid- 
ered as refrigeration systems. 

10.10.7 Installation in Commercial Garages and Aircraft Han- 
gars. Duct furnaces installed in garages for more than three 
motor vehicles or in aircraft hangars shall be of a listed type 
and shall be installed in accordance with 9.1.11 and 9.1.12. 

10.11 Floor Furnaces. 

10.11.1 Installation. The installation of floor furnaces shall 
comply with the following requirements: 

( 1 ) Listed floor furnaces shall be installed in accordance with 
the manufacturer's installation instructions. 

(2) Unlisted floor furnaces shall not be installed in combus- 
tible floors. 

(3) Thermostats controlling floor furnaces shall not be located 
in a room or space that can be separated from the room or 
space in which the register of the floor furnace is located. 

10.11.2 Temperature Limit Controls. 

10.11.2.1 Listed automatically operated floor furnaces shall 
be equipped with temperature limit controls. 

10.11.2.2 Unlisted automatically operated floor furnaces shall 
be equipped with a temperature limit control arranged to shut 
off the flow of gas to the burner in the event the temperature at 



2006 Edition 



54-76 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-76 



the warm air outlet register exceeds 350°F (177°C) above room 
temperature. 

10.11.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 9.3. 

10.11.4 Placement. The following provisions apply to fur- 
naces that serve one story: 

(1) Floors. Floor furnaces shall not be installed in the floor of 
any doorway, stairway landing, aisle, or passageway of any 
enclosure, public or private, or in an exitway from any 
such room or space. 

(2) Walls and Corners. The register of a floor furnace with a 
horizontal warm air outlet shall not be placed closer than 
6 in. (150 mm) from the nearest wall. Adistance of at least 
18 in. (460 mm) from two adjoining sides of the floor 
furnace register to walls shall be provided to eliminate the 
necessity of occupants walking over the warm air dis- 
charge. The remaining sides shall be a minimum of 6 in. 
(150 mm) from a wall. Wall register models shall not be 
placed closer than 6 in. (150 mm) to a corner. 

(3) Draperies. The furnace shall be placed so that a door, drap- 
ery, or similar object cannot be nearer than 12 in. 
(300 mm) to any portion of the register of the furnace. 

10.11.5 Bracing. The space provided for the furnace shall be 
framed with doubled joists and with headers not lighter than 
the joists. 

10.11.6 Support. Means shall be provided to support the fur- 
nace when the floor register is removed. 

10.11.7 Clearance. The lowest portion of the floor furnace shall 
have at least a 6 in. (150 mm) clearance from the general ground 
level. A reduced clearance to a minimum of 2 in. (50 mm) shall 
be permitted, provided the lower 6 in. (150 mm) portion of the 
floor furnace is sealed by the manufacturer to prevent entrance 
of water. Where these clearances are not present, the ground 
below and to the sides shall be excavated to form a "basin-like" pit 
under the furnace so that the required clearance is provided be- 
neath the lowest portion of the furnace. A 12 in. (300 mm) clear- 
ance shall be provided on all sides except the control side, which 
shall have an 18 in. (460 mm) clearance. 

10.11.8 Access. The space in which any floor furnace is in- 
stalled shall be accessible by an opening in the foundation not 
less than 24 in. x 18 in. (610 mm x 460 mm) or by a trapdoor 
not less than 24 in. x 24 in. (610 mm x 610 mm) in any cross 
secdon thereof, and a passageway not less than 24 in. x 18 in. 
(610 mm x 460 mm) in any cross section thereof. 

10.11.9 Seepage Pan. Where the excavation exceeds 12 in. 
(300 mm) in depth or water seepage is likely to collect, a water- 
tight copper pan, concrete pit, or other suitable material shall be 
used, unless adequate drainage is provided or the appliance is 
sealed by the manufacturer to meet this condition. A copper pan 
shall be made of not less than 16 oz/ft 2 (4.9 kg/m 2 ) sheet cop- 
per. The pan shall be anchored in place so as to prevent floating, 
and the walls shall extend at least 4 in. (100 mm) above the 
ground level with at least a 6 in. (150 mm) clearance on all sides, 
except on the control side, which shall have at least an 18 in. 
(460 mm) clearance. 

10.11.10 Wind Protection. Floor furnaces shall be protected, 
where necessary, against severe wind conditions. 

10.11.11 Upper Floor Installations. Listed floor furnaces shall 
be permitted to be installed in an upper floor, provided the fur- 
nace assembly projects below into a utility room, closet, garage, 



or similar nonhabitable space. In such installations, the floor fur- 
nace shall be enclosed completely (entirely separated from the 
nonhabitable space) with means for air intake to meet the provi- 
sions of Section 9.3, with access for servicing, minimum furnace 
clearances of 6 in. (150 mm) to all sides and bottom, and with the 
enclosure constructed of pordand cement plaster or metal lath 
or other noncombustible material. 

10.11.12 First Floor Installation. Listed floor furnaces installed 
in the first or ground floors of buildings shall not be required to 
be enclosed unless the basements of these buildings have been 
converted to apartments or sleeping quarters, in which case the 
floor furnace shall be enclosed as specified for upper floor instal- 
lations and shall project into a nonhabitable space. 

10.12 Food Service Appliance, Floor-Mounted. 

10.12.1 Clearance for Listed Appliances. Listed floor-mounted 
food service appliances, such as ranges for hotels and restau- 
rants, deep fat fryers, unit broilers, kettles, steam cookers, 
steam generators, and baking and roasting ovens, shall be in- 
stalled at least 6 in. (150 mm) from combustible material ex- 
cept that at least a 2 in. (50 mm) clearance shall be maintained 
between a draft hood and combustible material. Floor- 
mounted food service appliances listed for installation at 
lesser clearances shall be installed in accordance with the 
manufacturer's installation instructions. Appliances designed 
and marked "For use only in noncombustible locations" shall 
not be installed elsewhere. 

10.12.2 Clearance for Unlisted Appliances. Unlisted floor- 
mounted food service appliances shall be installed to provide 
a clearance to combustible material of not less than 18 in. 
(460 mm) from the sides and rear of the appliance and from 
the vent connector and not less than 48 in. (1.2 m) above 
cooking tops and at the front of the appliance. Clearances for 
unlisted appliances installed in partially enclosed areas such as 
alcoves shall not be reduced. Reduced clearances for unlisted 
appliances installed in rooms that are not partially enclosed 
shall be in accordance with Table 10.2.3(b). 

10.12.3 Mounting on Combustible Floor. 

10.12.3.1 Listed floor-mounted food service appliances that 
are listed specifically for installation on floors constructed of 
combustible material shall be permitted to be mounted on 
combustible floors in accordance with the manufacturer's in- 
stallation instructions. 

10.12.3.2 Floor-mounted food service appliances that are not 
listed for mounting on a combustible floor shall be mounted 
in accordance with 10.12.4 or be mounted in accordance with 
one of the following: 

(1) Where the appliance is set on legs that provide not less 
than 18 in. (460 mm) open space under the base of the 
appliance or where it has no burners and no portion of 
any oven or broiler within 18 in. (460 mm) of the floor, it 
shall be permitted to be mounted on a combustible floor 
without special floor protection, provided there is at least 
one sheet metal baffle between the burner and the floor. 

(2) Where the appliance is set on legs that provide not less than 
8 in. (200 mm) open space under the base of the appliance, 
it shall be permitted to be mounted on combustible floors, 
provided the floor under the appliance is protected with not 
less than % in. (9.5 mm) insulating millboard covered with 
sheet metal not less than 0.0195 in. (0.5 mm) thick. The 
preceding specified floor protection shall extend not less 
than 6 in. (150 mm) beyond the appliance on all sides. 



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INSTALLATION OF SPECIFIC APPLIANCES 



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(3) Where the appliance is set on legs that provide not less 
than 4 in. (100 mm) under the base of the appliance, it 
shall be permitted to be mounted on combustible floors, 
provided the floor under the appliance is protected with 
hollow masonry not less than 4 in. (100 mm) in thickness 
covered with sheet metal not less than 0.0195 in. 
(0.5 mm) thick. Such masonry courses shall be laid with 
ends unsealed and joints matched in such a way as to pro- 
vide for free circulation of air through the masonry. 

(4) Where the appliance does not have legs at least 4 in. 
(100 mm) high, it shall be permitted to be mounted on 
combustible floors, provided the floor under the appli- 
ance is protected by two courses of 4 in. (100 mm) hollow 
clay tile, or equivalent, with courses laid at right angles 
and with ends unsealed and joints matched in such a way 
as to provide for free circulation of air through such ma- 
sonry courses, and covered with steel plate not less than 
3 /i6 in. (4.8 mm) in thickness. 

10.12.4 Installation on Noncombustible Floor. 

10.12.4.1 Listed floor-installed food service appliances that 
are designed and marked "For use only in noncombustible 
locations" shall be installed on floors of noncombustible con- 
struction with noncombustible flooring and surface finish and 
with no combustible material against the underside thereof, 
or on noncombustible slabs or arches having no combustible 
material against the underside thereof. 

10.12.4.2 Such construction shall in all cases extend not less 
than 12 in. (300 mm) beyond the appliance on all sides. 

10.12.5 Combustible Material Adjacent to Cooking Top. Any 

portion of combustible material adjacent to a cooking top sec- 
tion of a food service range, even though listed for close-to- 
wall installation, that is not shielded from the wall by a high 
shelf, warming closet, and so on, shall be protected as speci- 
fied in 10.12.2 for a distance of at least 2 ft (0.6 m) above the 
surface of the cooking top. 

10.12.6 For Use with Casters. Floor-mounted appliances with 
casters shall be listed for such construction and shall be installed 
in accordance with the manufacturer's installation instructions 
for limiting the movement of the appliance to prevent strain on 
the connection. 

10.12.7 Level Installation. Floor-mounted food service appli- 
ances shall be installed level on a firm foundation. 

10.12.8* Ventilation. Means shall be provided to properly ven- 
tilate the space in which a food service appliance is installed to 
permit proper combustion of the gas. 

10.13 Food Service Appliances, Counter Appliances. 

10.13.1 Vertical Clearance. A vertical distance of not less than 
48 in. (1.2 m) shall be provided between the top of all food 
service hot plates and griddles and combustible material. 

10.13.2 Clearance for Listed Appliances. Listed food service 

counter appliances such as hot plates and griddles, food and dish 
warmers, and coffee brewers and urns, where installed on com- 
bustible surfaces, shall be set on their own bases or legs and shall 
be installed with a minimum horizontal clearance of 6 in. 
(150 mm) from combustible material, except that at least a 2 in. 
(50 mm) clearance shall be maintained between a draft hood 
and combustible material. Food service counter appliances listed 
for installation at lesser clearances shall be installed in accor- 
dance with the manufacturer's installation instructions. 



10.13.3 Clearance for Unlisted Appliances. Unlisted food ser- 
vice hot plates and griddles shall be installed with a horizontal 
clearance from combustible material of not less than 18 in. 
(460 mm). Unlisted gas food service counter appliances, in- 
cluding coffee brewers and urns, waffle bakers, and hot water 
immersion sterilizers, shall be installed with a horizontal clear- 
ance from combustible material of not less than 12 in. 
(300 mm). Reduced clearances for gas food service counter 
appliances shall be in accordance with Table 10.2.3(b). Un- 
listed food and dish warmers shall be installed with a horizon- 
tal clearance from combustible material of not less than 6 in. 
(150 mm). 

10.13.4 Mounting of Unlisted Appliances. Unlisted food ser- 
vice counter appliances shall not be set on combustible material 
unless they have legs that provide not less than 4 in. (100 mm) of 
open space below the burners and the combustible surface is 
protected with insulating millboard at least V* in. (6 mm) thick 
covered with sheet metal not less than 0.0122 in. (0.3 mm) thick, 
or with equivalent protection. 

10.14 Hot Plates and Laundry Stoves. 

10.14.1 Listed domestic hot plates and laundry stoves in- 
stalled on combustible surfaces shall be set on their own legs 
or bases. They shall be installed with minimum horizontal 
clearances of 6 in. (150 mm) from combustible material. 

10.14.2 Unlisted domestic hot plates and laundry stoves shall 
be installed with horizontal clearances to combustible mate- 
rial of not less than 12 in. (300 mm). Combustible surfaces 
under unlisted domestic hot plates and laundry stoves shall be 
protected in an approved manner. 

10.14.3 The vertical distance between tops of all domestic hot 
plates and laundry stoves and combustible material shall be at 
least 30 in. (760 mm). 

10.15 Household Cooking Appliances. 

10.15.1 Floor-Mounted Units. 

10.15.1.1 Clearance from Combustible Material. The clear- 
ances specified as follows shall not interfere with combustion 
air, accessibility for operation, and servicing: 

(1) Listed floor-mounted household cooking appliances, 
where installed on combustible floors, shall be set on 
their own bases or legs and shall be installed in accor- 
dance with the manufacturer's installation instructions. 

(2) Listed household cooking appliances with listed gas room 
heater sections shall be installed so that the warm air dis- 
charge side shall have a minimum clearance of 18 in. 
(460 mm) from adjacent combustible material. A mini- 
mum clearance of 36 in. (910 mm) shall be provided be- 
tween the top of the heater section and the bottom of 
cabinets. 

(3) Listed household cooking appliances that include a solid 
or liquid fuel-burning section shall be spaced from com- 
bustible material and otherwise installed in accordance 
with the manufacturer's installation instructions for the 
supplementary fuel section of the appliance. 

(4) Unlisted floor-mounted household cooking appliances 
shall be installed with at least a 6 in. (150 mm) clearance 
at the back and sides to combustible material. Combus- 
tible floors under unlisted appliances shall be protected 
in an approved manner. 



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NATIONAL FUEL GAS CODE 



ANSI Z223.1-78 



10.15.1.2 Vertical Clearance Above Cooking Top. Household 
cooking appliances shall have a vertical clearance above the 
cooking top of not less than 30 in. (760 mm) to combustible 
material or metal cabinets. A minimum clearance of 24 in. 
(610 mm) is permitted when one of the following is installed: 

(1) The underside of the combustible material or metal cabi- 
net above the cooking top is protected with not less than 
'A in. (6 mm) insulating millboard covered with sheet 
metal not less than 0.0122 in. (0.3 mm) thick. 

(2) A metal ventilating hood of sheet metal not less than 
0.0122 in. (0.3 mm) thick is installed above the cooking 
top with a clearance of not less than l A in. (6 mm) be- 
tween the hood and the underside of the combustible 
material or metal cabinet, and the hood is at least as wide 
as the appliance and is centered over the appliance. 

(3) A listed cooking appliance or microwave oven is installed 
over a listed cooking appliance and will conform to the 
terms of the upper appliance's manufacturer's installation 
instructions. 

10.15.1.3 Level Installation. Cooking appliances shall be in- 
stalled so that the cooking top or oven racks are level. 

10.15.2 Built-in Units. 

10.15.2.1 Installation. Listed built-in household cooking ap- 
pliances shall be installed in accordance with the manufactur- 
er's installation instructions. The installation shall not inter- 
fere with combustion air, accessibility for operation, and 
servicing. Unlisted built-in household cooking appliances 
shall not be installed in, or adjacent to, combustible material. 

10.15.2.2 Vertical Clearance. Built-in top (or surface) cooking 
appliances shall have a vertical clearance above the cooking 
top of not less than 30 in. (760 mm) to combustible material 
or metal cabinets. A minimum clearance of 24 in. (610 mm) 
shall be permitted when one of the following is installed: 

(1) The underside of the combustible material or metal cabi- 
net above the cooking top is protected with not less than 
Vi in. (6 mm) insulating millboard covered with sheet 
metal not less than 0.0122 in. (0.3 mm) thick. 

(2) A metal ventilating hood of sheet metal not less than 
0.0122 in. (0.3 mm) thick is installed above the cooking 
top with a clearance of not less than l A in. (6 mm) be- 
tween the hood and the underside of the combustible 
material or metal cabinet, and the hood is at least as wide 
as the appliance and is centered over the appliance. 

(3) A listed cooking appliance or microwave oven is installed 
over a listed cooking appliance and will conform to the 
terms of the upper appliance manufacturer's installation 
instructions. 

10.15.2.3 Horizontal Clearance. The minimum horizontal 
distance from the center of the burner head(s) of a listed top 
(or surface) cooking appliance to vertical combustible walls 
extending above the top panel shall be not less than that dis- 
tance specified by the permanent marking on the appliance. 

10.15.2.4 Level Installation. Built-in household cooking ap- 
pliances shall be installed so that the cooking top, broiler pan, 
or oven racks are level. 

10.16 Illuminating Appliances. 

10.16.1 Clearances for Listed Appliances. Listed illuminating 
appliances shall be installed in accordance with the manufac- 
turer's installation instructions. 



10.16.2 Clearances for Unlisted Appliances. 

10.16.2.1 Enclosed Type. Clearance shall comply with the fol- 
lowing: 

(1) Unlisted enclosed illuminating appliances installed out- 
doors shall be installed with clearances in any direction from 
combustible material of not less than 12 in. (300 mm). 

(2) Unlisted enclosed illuminating appliances installed indoors 
shall be installed with clearances in any direction from com- 
bustible material of not less than 18 in. (460 mm). 

10.16.2.2 Open-Flame Type. Clearance shall comply with the 
following: 

(1) Unlisted open-flame illuminating appliances installed out- 
doors shall have clearances from combustible material not 
less than that specified in Table 10.16.2.2. The distance from 
ground level to the base of the burner shall be a minimum of 
7 ft (2.1 m) where installed within 2 ft (0.6 m) of walkways. 
Lesser clearances shall be permitted to be used where ac- 
ceptable to the authority havingjurisdiction. 

(2) Unlisted open-flame illuminating appliances installed 
outdoors shall be equipped with a limiting orifice or 
other limiting devices that will maintain a flame height 
consistent with the clearance from combustible material, 
as given in Table 10.16.2.2. 

(3) Appliances designed for flame heights in excess of 30 in. 
(760 mm) shall be permitted to be installed if acceptable to 
the authority havingjurisdiction. Such appliances shall be 
equipped with a safety shutoff device or automatic ignition. 

(4) Unlisted open-flame illuminating appliances installed in- 
doors shall have clearances from combustible material ac- 
ceptable to the authority havingjurisdiction. 



Table 10.16.2.2 Clearances for Unlisted 
Outdoor Open-Flame Illuminating Appliances 





Minimum Clearance 




from Combustible 


Flame Height 


Material (ft)* 






(in.) 


Horizontal Vertical 


12 


2 6 


18 


3 8 


24 


3 10 


30 


4 12 



For SI units, 1 in. = 25.4 mm; 1 ft = 0.305 m. 
*Measured from the nearest portion of the burner head. 



10.16.3 Mounting on Buildings. Illuminating appliances de- 
signed for wall or ceiling mounting shall be securely attached 
to substantial structures in such a manner that they are not 
dependent on the gas piping for support. 

10.16.4 Mounting on Posts. Illuminating appliances designed 
for post mounting shall be securely and rigidly attached to a 
post. Posts shall be rigidly mounted. The strength and rigidity 
of posts greater than 3 ft (0.9 m) in height shall be at least 
equivalent to that of a 2Vi in. (64 mm) diameter post con- 
structed of 0.064 in. (1.6 mm) thick steel or a 1 in. Schedule 40 
steel pipe. Posts 3 ft (0.9 m) or less in height shall not be 
smaller than a S A in. Schedule 40 steel pipe. Drain openings 



2006 Edition 



ANSI Z223. 1-79 



INSTALLATION OF SPECIFIC APPLIANCES 



54-79 



shall be provided near the base of posts where there is a possi- 
bility of water collecting inside them. 

10.16.5 Appliance Pressure Regulators. Where an appliance 
pressure regulator is not supplied with an illuminating appliance 
and the sendee line is not equipped with a service pressure regu- 
lator, an appliance pressure regulator shall be installed in the line 
serving one or more illuminating appliances. 

10.17 Incinerators, Commercial-Industrial. Commercial- 
industrial-type incinerators shall be constructed and installed 
in accordance with NFPA 82, Standard on Incinerators and Waste 
and Linen Handling Systems and Equipment. 

10.18 Infrared Heaters. 

10.18.1 Support. Suspended-type infrared heaters shall be 
fixed in position independent of gas and electric supply lines. 
Hangers and brackets shall be of noncombustible material. 
Heaters subject to vibration shall be provided with vibration- 
isolating hangers. 

10.18.2 Clearance. The installation of infrared heaters shall 
meet the following clearance requirements: 

( 1 ) Listed heaters shall be installed with clearances from com- 
bustible material in accordance the manufacturer's instal- 
lation instructions. 

(2) Unlisted heaters shall be installed in accordance with 
clearances from combustible material acceptable to the 
authority having jurisdiction. 

(3) In locations used for the storage of combustible materials, 
signs shall be posted to specify the maximum permissible 
stacking height to maintain required clearances from the 
heater to the combustibles. 

10.18.3 Combustion and Ventilation Air. 

10.18.3.1 Where unvented infrared heaters are used, natural 
or mechanical means shall be provided to supply and exhaust 
at least 4 ft 3 /min/1000 Btu/hr (0.38 m 3 /niin/kW) input of 
installed heaters. 

10.18.3.2 Exhaust openings for removing flue products shall 
be above the level of the heaters. 

10.18.4 Installation in Commercial Garages and Aircraft Han- 
gars. Overhead heaters installed in garages for more than 
three motor vehicles or in aircraft hangars shall be of a listed 
type and shall be installed in accordance with 9.1.11 and 
9.1.12. 

10.19 Open-Top Broiler Units. 

10.19.1 Listed Units. Listed open-top broiler units shall be 
installed in accordance with the manufacturer's installation 
instructions. 

10.19.2 Unlisted Units. Unlisted open-top broiler units shall 
be installed in accordance with the manufacturers' instruc- 
tions but shall not be installed in combustible material. 

10.19.3 Protection Above Domestic Units. Domestic open-top 
broiler units shall be provided with a metal ventilating hood 
not less than 0.0122 in. (0.3 mm) thick with a clearance of not 
less than Vi in. (6 mm) between the hood and the underside of 
combustible material or metal cabinets. A clearance of at least 
24 in. (610 mm) shall be maintained between the cooking top 
and the combustible material or metal cabinet, and the hood 
shall be at least as wide as the open-top broiler unit and cen- 
tered over the unit. Listed domestic open-top broiler units 



incorporating an integral exhaust system and listed for use 
without a ventilating hood need not be provided with a venti- 
lating hood if installed in accordance with 10.15.1.2(1). 

10.19.4 Commercial Units. Commercial open-top broiler 
units shall be provided with ventilation in accordance with 

NFPA 96, Standard for Ventilation Control and Fire Protection of 
Commercial Cooking Operations. 

10.20 Outdoor Cooking Appliances. 

10.20. 1 Listed Units. Listed outdoor cooking appliances shall 
be installed in accordance with the manufacturer's installa- 
tion instructions. 

10.20.2 Unlisted Units. Unlisted outdoor cooking appliances 
shall be installed outdoors with clearances to combustible ma- 
terial of not less than 36 in. (910 mm) at the sides and back 
and not less than 48 in. (1220 mm) at the front. In no case 
shall the appliance be located under overhead combustible 
construction. 

10.21 Pool Heaters. 

10.21.1 Location. Apool heater shall be located or protected so 
as to minimize accidental contact of hot surfaces by persons. 

10.21.2 Clearance. The installation of pool heaters shall meet 
the following requirements: 

(1) In no case shall the clearances be such as to interfere with 
combustion air, draft hood or vent terminal clearance 
and relief, and accessibility for servicing. 

(2) A listed pool heater shall be installed in accordance with 
the manufacturer's installation instructions. 

(3) An unlisted pool heater shall be installed with a minimum 
clearance of 12 in. (300 mm) on all sides and the rear. A 
combustible floor under an unlisted pool heater shall be 
protected in an approved manner. 

10.21.3 Temperature- or Pressure-Limiting Devices. 

10.21.3.1 An unlisted pool heater shall be provided with over- 
temperature protection or overtemperature and overpressure 
protection by means of an approved device (s). 

10.21.3.2 Where a pool heater is provided with overtempera- 
ture protection only and is installed with any device in the 
discharge line of the heater that can restrict the flow of water 
from the heater to the pool (such as a check valve, shutoff 
valve, therapeutic pool valving, or flow nozzles), a pressure 
relief valve shall be installed either in the heater or between 
the heater and the restrictive device. 

10.21.4 Bypass Valves. Where an integral bypass system is not 
provided as a part of the pool heater, a bypass line and valve 
shall be installed between the inlet and outlet piping for use in 
adjusting the flow of water through the heater. 

10.21.5 Venting. Apool heater listed for outdoor installation 
shall be installed with the venting means supplied by the 
manufacturer and in accordance with the manufacturer's in- 
structions. (See 12.3.5, 12.3.6, 12.4.3, andSection 12.9.) 

10.22 Refrigerators. 

10.22.1 Clearance. Refrigerators shall be provided with clear- 
ances for ventilation at the top and back in accordance with 
the manufacturers' instructions. Where such instructions are 
not available, at least 2 in. (50 mm) shall be provided between 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSI Z223. 1-80 



the back of the refrigerator and the wall and at least 12 in. 
(300 mm) above the top. 

10.22.2 Venting or Ventilating Kits Approved for Use with a 
Refrigerator. Where an accessory kit is used for conveying air 
for burner combustion or unit cooling to the refrigerator 
from areas outside the room in which it is located, or for con- 
veying combustion products diluted with air containing waste 
heat from the refrigerator to areas outside the room in which 
it is located, the kit shall be installed in accordance with the 
refrigerator manufacturer's instructions. 

10.23 Room Heaters. 

10.23.1* Prohibited Installations. Unvented room heaters 
shall not be installed in bathrooms or bedrooms. 

Exception No. 1: Where approved by the authority having jurisdic- 
tion, one listed wall-mounted, unvented room heater equipped with 
an oxygen depletion safety shutoff system shall be permitted to be 
installed in a bathroom, provided that the input rating does not 
exceed 6000 Btu/hr (1 760 W/hr) and combustion and ventilation 
air is provided as specified in 10.1.2. 

Exception No. 2: Where approved by the authority having jurisdic- 
tion, one listed wall-mounted unvented room heater equipped with 
an oxygen depletion safety shutoff system shall be permitted to be 
installed in a bedroom, provided that the input rating does not 
exceed 10,000 Btu/hr (2930 W/hr) and combustion and ventila- 
tion air is provided as specified in 10.1.2. 

10.23.2 Installations in Institutions. Room heaters shall not 
be installed in the following occupancies: 

(1) Residential board and care 

(2) Health care 

10.23.3 Clearance. A room heater shall be placed so as not to 
cause a hazard to walls, floors, curtains, furniture, doors when 
open, and so on, and to the free movements of persons within 
the room. Heaters designed and marked "For use in noncombus- 
dble fireplace only" shall not be installed elsewhere. Listed room 
heaters shall be installed in accordance with the manufacturer's 
installation instructions. In no case shall the clearances be such as 
to interfere with combustion air and accessibility. Unlisted room 
heaters shall be installed with clearances from combustible mate- 
rial not less than the following: 

(1) Circulating Type. Room heaters having an outer jacket sur- 
rounding the combustion chamber, arranged with open- 
ings at top and bottom so that air circulates between the 
inner and outer jacket, and without openings in the outer 
jacket to permit direct radiation, shall have clearance at 
sides and rear of not less than 12 in. (300 mm). 

(2) Radiating Type. Room heaters other than those of the cir- 
culating type described in 10.23.3(1) shall have clearance 
at sides and rear of not less than 18 in. (460 mm), except 
that heaters that make use of metal, asbestos, or ceramic 
material to direct radiation to the front of the heater shall 
have a clearance of 36 in. (910 mm) in front and, if con- 
structed with a double back of metal or ceramic, shall be 
permitted to be installed with a clearance of 18 in. 
(460 mm) at sides and 12 in. (300 mm) at rear. Combus- 
tible floors under unlisted room heaters shall be pro- 
tected in an approved manner. 

10.23.4 Wall-Type Room Heaters. Wall-type room heaters 
shall not be installed in or attached to walls of combustible 
material unless listed for such installation. 



10.24 Stationary Gas Engines. The installation of gas engines 
shall conform to NFPA 37, Standard for the Installation and Use of 
Stationary Combustion Engines and Gas Turbines. 

10.25 Gas-Fired Toilets. 

10.25.1 Clearance. A listed gas-fired toilet shall be installed in 
accordance with the manufacturer's installation instructions, 
provided that the clearance is in any case sufficient to afford 
ready accessibility for use, cleanout, and necessary servicing. 

10.25.2 Mounting. Listed gas-fired toilets installed on com- 
bustible floors shall be listed for such installation. 

10.25.3 Installation. Vents or vent connectors that are capable 
of being contacted during casual use of the room in which the 
toilet is installed shall be protected or shielded to prevent such 
contact. 

10.26 Unit Heaters. 

10.26.1 Support. Suspended-type unit heaters shall be safely 
and adequately supported, with due consideration given to 
their weight and vibration characteristics. Hangers and brack- 
ets shall be of noncombustible material. 

10.26.2 Clearance. 

10.26.2.1 Suspended-Type Unit Heaters. Suspended-type 
unit heaters shall meet the following requirements: 

( 1 ) A listed unit heater shall be installed with clearances from 
combustible material of not less than 18 in. (460 mm) at 
the sides, 12 in. (300 mm) at the bottom, and 6 in. 
(150 mm) above the top where the unit heater has an 
internal draft hood, or 1 in. (25 mm) above the top of the 
sloping side of a vertical draft hood. A unit heater listed 
for reduced clearances shall be installed in accordance 
with the manufacturer's installation instructions. 

(2) Unlisted unit heaters shall be installed with clearances to 
combustible material of not less than 18 in. (460 mm). 

(3) Clearances for servicing shall be in accordance with the 
manufacturers' recommendations contained in the instal- 
lation instructions. 

10.26.2.2 Floor-Mounted-iype Unit Heaters. Floor-mounted- 
type unit heaters shall meet the following requirements: 

( 1 ) A listed unit heater shall be installed with clearances from 
combustible material at the back and one side only of not 
less than 6 in. (150 mm). Where the flue gases are vented 
horizontally, the 6 in. (150 mm) clearance shall be mea- 
sured from the draft hood or vent instead of the rear wall 
of the unit heater. A unit heater listed for reduced clear- 
ances shall be installed in accordance with the manufac- 
turer's installation instructions. 

(2) Floor-mounted-type unit heaters installed on combustible 
floors shall be listed for such installation. 

(3) Combustible floors under unlisted floor-mounted unit 
heaters shall be protected in an approved manner. 

(4) Clearances for servicing shall be in accordance with the 
manufacturers' recommendations contained in the instal- 
lation instructions. 

10.26.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 9.3. 

10.26.4 Ductwork. A unit heater shall not be attached to a 
warm air duct system unless listed and marked for such instal- 
lation. 



2006 Edition 



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INSTALLATION OF SPECIFIC APPLIANCES 



54-81 



10.26.5 Installation in Commercial Garages and Aircraft Han- 
gars. Unit heaters installed in garages for more than three 
motor vehicles or in aircraft hangars shall be of a listed type 
and shall be installed in accordance with 9.1.11 and 9.1.12. 

10.27 Wall Furnaces. 

10.27.1 Installation. 

10.27.1.1 Listed wall furnaces shall be installed in accordance 
with the manufacturer's installation instructions. Wall fur- 
naces installed in or attached to combustible material shall be 
listed for such installation. 

10.27.1.2 Unlisted wall furnaces shall not be installed in or 
attached to combustible material. 

10.27.1.3 Vented wall furnaces connected to a Type B-W gas 
vent system listed only for a single story shall be installed only 
in single-story buildings or the top story of multistory build- 
ings. Vented wall furnaces connected to a Type B-W gas vent 
system listed for installation in multistory buildings shall be 
permitted to be installed in single-story or multistory build- 
ings. Type B-W gas vents shall be attached directly to a solid 
header plate that serves as a firestop at that point and that 
shall be permitted to be an integral part of the vented wall 
furnace. The stud space in which the vented wall furnace is 
installed shall be ventilated at the first ceiling level by installa- 
tion of the ceiling plate spacers furnished with the gas vent. 
Firestop spacers shall be installed at each subsequent ceiling 
or floor level penetrated by the vent. (See Figure 10.27.1.3 for 
Type B-W gas vent installation.) 



Installation of B-W gas 
vent for each subsequent 
ceiling or floor level of 
multistory buildings 




Firestop spacers supplied 
by manufacturer of B-W 
gas vent 



Plate cut away to provide 
passage of B-W gas vent 



Installation of B-W gas 
vent for single-story 
buildings or for first-floor 
or multistory buildings 




Header plate of 
vented wall furnace 
(also acts as firestop) 



Use manufacturer's 
method of fastening 
pipe to base plate 



Nail firestop 
spacer securely 



Ceiling plate spacers to center 
B-W gas vent in stud space — 
nail securely at both ends 



Plate cut away for full width of 
stud space to provide ventilation 

_ Studs on 16 in. (410 mm) 
centers 



Sheet metal screw 
base plate to header 



FIGURE 10.27.1.3 Installation of Type B-W Gas Vents for 
Vented Wall Furnaces. 



10.27.1.4 Direct-vent wall furnaces shall be installed with the 
vent-air intake terminal in the outdoors. The thickness of the 
walls on which the furnace is mounted shall be within the 
range of wall thickness marked on the furnace and covered in 

the manufacturers' installation instructions. 

10.27.1.5 Panels, grilles, and access doors that are required to 
be removed for normal servicing operations shall not be at- 
tached to the building. (For additional information on the venting 
of wall furnaces, see Chapter 12.) 

10.27.2 Location. Wall furnaces shall be located so as not to 
cause a hazard to walls, floors, curtains, furniture, or doors. 
Wall furnaces installed between bathrooms and adjoining 
rooms shall not circulate air from bathrooms to other parts of 
the building. 

10.27.3 Combustion and Circulating Air. Combustion and cir- 
culating air shall be provided in accordance with Section 9.3. 

10.28 Water Heaters. 

10.28.1 Location. Water heater installations in bedrooms and 
bathrooms shall comply with one of the following: 

(1) Water heater shall be installed in a closet equipped with a 
weather-stripped door with a self-closing device, and all 
combustion air shall be obtained from the outdoors in 
accordance with 9.3.3. 

(2) Water heater shall be of the direct-vent type. 

10.28.2 Clearance. 

10.28.2.1 The clearances shall not be such as to interfere with 
combustion air, draft hood clearance and relief, and accessi- 
bility for servicing. Listed water heaters shall be installed in 
accordance with the manufacturer's installation instructions. 

10.28.2.2 Unlisted water heaters shall be installed with a 
clearance of 12 in. (300 mm) on all sides and rear. Combus- 
tible floors under unlisted water heaters shall be protected in 
an approved manner. 

10.28.3 Pressure-Limiting Devices. A water heater installation 
shall be provided with overpressure protection by means of an 
approved, listed device installed in accordance with the manu- 
facturer's installation instructions. The pressure setting of the 
device shall exceed the water service pressure and shall not 
exceed the maximum pressure rating of the water heater. 

10.28.4 Temperature-Limiting Devices. A water heater installa- 
tion or a hot water storage vessel installation shall be provided 
with overtemperature protection by means of an approved, listed 
device installed in accordance with the manufacturer's installa- 
tion instructions. 

10.28.5 Temperature, Pressure, and Vacuum Relief Devices. 

Temperature, pressure, and vacuum relief devices or combi- 
nations thereof, and automatic gas shutoff devices, shall be 
installed in accordance with the manufacturer's installation 
instructions. A shutoff valve shall not be placed between the 
relief valve and the water heater or on discharge pipes be- 
tween such valves and the atmosphere. The hourly Btu dis- 
charge capacity or the rated steam relief capacity of the device 
shall not be less than the input rating of the water heater. 

10.28.6 Automatic Instantaneous Type: Cold Water Supply. 

The water supply to an automatic instantaneous water heater 
that is equipped with a water flow-actuated control shall be 
such as to provide sufficient pressure to properly operate the 



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ANSI Z223.1-82 



control when water is drawn from the highest faucet served by 
the heater. 

10.28.7* Antisiphon Devices. Means acceptable to the author- 
ity having jurisdiction shall be provided to prevent siphoning 
in any water heater or any tank to which a circulating water 
heater that incorporates a cold water inlet tube is attached. 

10.29 Compressed Natural Gas (CNG) Vehicular Fuel Systems. 

The installation of compressed natural gas (CNG) fueling 
(dispensing) systems shall conform to NFPA 52, Compressed 
Natural Gas (CNG) Vehicular Fuel Systems Code. 

10.30 Appliances for Installation in Manufactured Housing. 

Appliances installed in manufactured housing after the initial 
sale shall be listed for installation in manufactured housing, or 
approved, and shall be installed in accordance with the re- 
quirements of this code and the manufacturers' installation 
instructions. Appliances installed in the living space of manu- 
factured housing shall be in accordance with the require- 
ments of Section 9.3. 

10.31 Fuel Cell Power Plants. Fuel cell power plants with a 
power output of less than 50 kW shall be listed and installed in 
accordance with the manufacturer's instructions. Fuel cell 
power plants with a power output of greater than 50 kW shall 
be installed in accordance with NFPA 853, Standard for the In- 
stallation of Stationary Fuel Cell Power Systems. 



Chapter 11 Procedures to Be Followed to Place 
Appliance in Operation 

11.1 Adjusting the Burner Input. 

11.1.1* Adjusting Input. The input rate of the burner shall be 
adjusted to the proper value in accordance with the appliance 
manufacturer's instructions. Firing at a rate in excess of the 
nameplate rating shall be prohibited. 

11.1.1.1 The input rate can be adjusted by either changing 
the size of a fixed orifice, changing the adjustment of an ad- 
justable orifice, or readjusting the appliance's gas pressure 
regulator oudet pressure (where a regulator is provided in the 
appliance). 

11.1.1.2 Input rate can be determined by either one of the 
following: 

( 1 ) Checking burner input by using a gas meter 

(2) Checking burner input by using orifice pressure drop and 
orifice size 

11.1.1.3 Overfiring shall be prohibited. 

11.1.2 High Altitude. Gas input ratings of appliances shall be 
used for elevations up to 2000 ft (600 m) . The input ratings of 
appliances operating at elevations above 2000 ft (600 m) shall 
be reduced in accordance with one of the following methods: 

(1) At the rate of 4 percent for each 1000 ft (300 m) above sea 
level before selecting appropriately sized appliance. 

(2) As permitted by the authority having jurisdiction. 

(3) Listed appliances derated in accordance with the manu- 
facturer's installation instructions shall be permitted. 

11.2* Primary Air Adjustment. The primary air for injection 
(Bunsen)-type burners shall be adjusted for proper flame 



characteristics in accordance with the appliance manufactur- 
ers' instructions. After setting the primary air, the adjustment 
means shall be secured in position. 

11.3 Safety Shutoff Devices. Where a safety shutoff device is 
provided, it shall be checked for proper operation and adjust- 
ment in accordance with the appliance manufacturer's in- 
structions. Where the device does not function properly to 
turn off the gas supply in the event of pilot outage or other 
improper operation, it shall be properly serviced or replaced 
with a new device. 

11.4 Automatic Ignition. Appliances supplied with means for 
automatic ignition shall be checked for proper operation. If 
necessary, proper adjustments shall be made. 

11.5 Protective Devices. All protective devices furnished with the 
appliance, such as a limit control, fan control to blower, tempera- 
ture and pressure relief valve, low-water cutoff device, or manual 
operating features, shall be checked for proper operation. 

11.6* Checking the Draft. Vent-connected appliances shall be 
operated for several minutes and checked to see that the com- 
bustion products are going up the chimney or gas vent prop- 
erly, by passing a lighted match or taper around the edge of 
the relief opening of the draft hood. Where the chimney or 
gas vent is drawing properly, the match flame will be drawn 
into the draft hood. Where not, the combustion products will 
tend to extinguish this flame. Where the combustion products 
are escaping from the relief opening of the draft hood, the 
appliance shall not be operated until proper adjustments or 
repairs are made to provide adequate draft through the chim- 
ney or gas vent. 

11.7 Operating Instructions. Operating instructions shall be 
furnished and shall be left in a prominent position near the 
appliance for the use of the consumer. 

Chapter 12 Venting of Appliances 

12.1 Minimum Safe Performance. A venting system shall be 
designed and constructed so as to develop a positive flow ad- 
equate to convey flue or vent gases to the outdoors. 

12.2 General. 

12.2.1 General. This chapter recognizes that the choice of vent- 
ing materials and the methods of installation of venting systems 
are dependent on the operating characteristics of the appliance. 

12.2.2 Categories. The operating characteristics of vented ap- 
pliances can be categorized with respect to (1) positive or 
negative pressure within the venting system and (2) whether 
or not the appliance generates flue or vent gases that can con- 
dense in the venting system. (See Section 3.3 for the definition of 
these vented appliance categories.) 

12.2.3 Installation. Listed vents shall be installed in accor- 
dance with Chapter 12 and the manufacturer's installation 
instructions. 

12.3 Specification for Venting. 

12.3.1 Connection to Venting Systems. Except as permitted in 

12.3.2 through 12.3.6, all appliances shall be connected to 
venting systems. 

12.3.2 Appliances Not Required to Be Vented. The following 
appliances shall not be required to be vented. Where any or all 
of these appliances in 12.3.2(5) through (11) are installed so 
the aggregate input rating exceeds 20 Btu/hr/ft 3 (207 W/m 3 ) 
of room or space in which it is installed, one or more shall be 
provided with venting systems or other approved means for 



2006 Edition 



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VENTING OF APPLIANCES 



54-83 



conveying the vent gases to the outdoors so the aggregate input 
rating of the remaining unvented appliances does not exceed 
20 Btu/hr/ft 3 (207 W/m 3 ). Where the calculation includes the 
volume of an adjacent room or space, the room or space in which 
the appliances are installed shall be directly connected to the 
adjacent room or space by a doorway, archway, or other opening 
of comparable size that cannot be closed. 

(1) Listed ranges 

(2) Built-in domestic cooking units listed and marked for 
optional venting 

(3) Listed hot plates and listed laundry stoves 

(4) Listed Type 1 clothes dryers exhausted in accordance 
with Section 10.4 

(5) A single listed booster-type (automatic instantaneous) 
water heater, when designed and used solely for the sani- 
tizing rinse requirements of a dishwashing machine, pro- 
vided that the appliance is installed with the draft hood 
in place and unaltered, if a draft hood is required, in a 
commercial kitchen having a mechanical exhaust sys- 
tem; where installed in this manner, the draft hood out- 
let shall not be less than 36 in. (910 mm) vertically and 
6 in. (150 mm) horizontally from any surface other than 
the appliance. 

(6) Listed refrigerators 

(7) Counter appliances 

(8) Room heaters listed for unvented use (see 10.23.1 and 
10.23.2) 

(9) Direct gas-fired make-up air heaters 

(10) Other appliances listed for unvented use and not pro- 
vided with flue collars 

(11) Specialized appliances of limited input such as labora- 
tory burners or gas lights. 

12.3.3* Ventilating Hoods. Ventilating hoods and exhaust sys- 
tems shall be permitted to be used to vent appliances installed 
in commercial applications (see 12.4.4) and to vent industrial 
appliances, particularly where the process itself requires fume 
disposal. (See 9.1.6 and 9.1.9.) 

12.3.4 Well-Ventilated Spaces. The operation of industrial ap- 
pliances such that its flue gases are discharged directly into a 
large and well-ventilated space shall be permitted. 

12.3.5 Direct-Vent Appliances. Listed direct-vent appliances 
shall be installed in accordance with the manufacturer's instal- 
lation instructions and 12.9.3. 

1 2.3.6 Appliances with Integral Vents. Appliances incorporat- 
ing integral venting means shall be considered properly 
vented where installed in accordance with the manufacturer's 
installation instructions and 12.9.1 and 12.9.2. 

12.4 Design and Construction. 

12.4.1 Appliance Draft Requirements. A venting system shall 
satisfy the draft requirements of the appliance in accordance 
with the manufacturer's instructions. 

12.4.2 Design and Construction. Appliances required to be 
vented shall be connected to a venting system designed and 
installed in accordance with the provisions of Sections 12.5 
through 12.16. 

12.4.3 Mechanical Draft Systems. 

12.4.3.1 Mechanical draft systems shall be listed and shall be 
installed in accordance with both the appliance and the me- 
chanical draft system manufacturer's installation instructions. 



12.4.3.2 Appliances requiring venting shall be permitted to 
be vented by means of mechanical draft systems of either 
forced or induced draft design. 

Exception: Incinerators. 

12.4.3.3 Forced draft systems and all portions of induced 
draft systems under positive pressure during operation shall 
be designed and installed so as to prevent leakage of flue or 
vent gases into a building. 

12.4.3.4 Vent connectors serving appliances vented by natu- 
ral draft shall not be connected into any portion of mechani- 
cal draft systems operating under positive pressure. 

12.4.3.5 Where a mechanical draft system is employed, provi- 
sion shall be made to prevent the flow of gas to the main burners 
when the draft system is not performing so as to satisfy the oper- 
ating requirements of the appliance for safe performance. 

12.4.3.6 The exit terminals of mechanical draft systems shall 
be not less than 7 ft (2.1 m) above grade where located adja- 
cent to public walkways and shall be located as specified in 
12.9.1 and 12.9.2. 

12.4.4* Ventilating Hoods and Exhaust Systems. 

12.4.4.1 Ventilating hoods and exhaust systems shall be per- 
mitted to be used to vent appliances installed in commercial 
applications. 

12.4.4.2 Where automatically operated appliances are vented 
through a ventilating hood or exhaust system equipped with a 
damper or with a power means of exhaust, provisions shall be 
made to allow the flow of gas to the main burners only when 
the damper is open to a position to properly vent the appli- 
ance and when the power means of exhaust is in operation. 

12.4.5 Circulating Air Ducts, Above Ceiling Air-Handling 
Spaces, and Furnace Plenums. 

12.4.5.1 No portion of a venting system shall extend into or 
pass through any circulating air duct or furnace plenum. 

12.4.5.2 Where a venting system passes through an above- 
ceiling air space or other non-ducted portion of an air- 
handling system, it shall conform to one of the following re- 
quirements: 

(1) The venting system shall be a listed Special Gas Vent, other 
system serving a Category III or Category IV appliance, or 
other positive pressure vent, with joints sealed in accordance 
with the appliance or vent manufacturer's instructions. 

(2) The vent system shall be installed such that no fittings or 
joints between sections are installed in the above-ceiling 
space. 

(3) The venting system shall be installed in a conduit or en- 
closure with joints between the interior of the enclosure 
and the ceiling space sealed. 

12.5 T^pe of Venting System to Be Used. 

12.5.1 The type of venting system to be used shall be in accor- 
dance with Table 12.5.1. 

12.5.2 Plastic Piping. Plastic piping used for venting appli- 
ances listed for use with such venting materials shall be 
approved. 



2006 Edition 



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NATIONAL FUEL GAS CODE 



ANSI Z223. 1-84 



Table 1 2.5.1 Type of Venting System to Be 
Used 



Appliances 



Type of Venting System 



Listed Category I appliances 
Listed appliances equipped 
with draft hood 
Appliances listed for use with 
Type B gas vent 



Type B gas vent (see 12. 7) 
Chimney (see 12.6) 
Single-wall metal pipe 
(see 12.8) 

Listed chimney lining 
system for gas venting 
(see 12.6.1.3) 

Special gas vent listed for 
these appliances 
(see 12.5.3) 



Listed vented wall furnaces 



Type B-W gas vent 
(see 12.7, 10.27) 



Category II appliances 
Category III appliances 
Category IV appliances 



As specified or furnished 
by manufacturers of 
listed appliances 
(see 12.5.2, 12.5.3) 



Incinerators, outdoors 



Single-wall metal pipe 
[see 12.8, 12.8.3(3)] 



Incinerators, indoors 

Appliances that can be 

converted to use of solid fuel 
Unlisted combination gas- and 

oil-burning appliances 
Combination gas- and 

solid-fuel-burning appliances 
Appliances listed for use with 

chimneys only 
Unlisted appliances 



Chimney (see 12.6) 



Listed combination gas- and 
oil-burning appliances 



Type L vent (see 12.7) or 
chimney (see 12.6) 



Decorative appliance in vented Chimney (see 10.6.2) 
fireplace 



Gas-fired toilets 



Single-wall metal pipe 
(see 12.8, 10.25.3) 



Direct-vent appliances 



See 12.3.5 



Appliances with integral vents See 12.3.6 



12.5.3 Special Gas Vent. Special gas vent shall be listed and 
installed in accordance with the special gas vent manufactur- 
er's installation instructions. 

12.6 Masonry, Metal, and Factory-Built Chimneys. 

1 2.6. 1 Listing or Construction. 

12.6.1.1 Factory-built chimneys shall be installed in accordance 
with the manufacturer's installation instructions. Factory-built 
chimneys used to vent appliances that operate at positive vent 
pressure shall be listed for such application. 



12.6.1.2 Metal chimneys shall be built and installed in accor- 
dance with NFPA 211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances. 

12.6.1.3* Masonry chimneys shall be built and installed in ac- 
cordance with NFPA 211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances, and lined with approved clay 
flue lining, a listed chimney lining system, or other approved 
material that will resist corrosion, erosion, softening, or crack- 
ing from vent gases at temperatures up to 1800°F (982°C). 

Exception: Masonry chimney flues lined with a chimney lining system 
specifically listed for use with listed appliances with draft hoods, Category 
I appliances, and other appliances listed for use with Type B vents shall be 
permitted. The liner shall be installed in accordance with the liner manu- 
facturer's installation instructions. A permanent identifying label shall be 
attached at the point where the connection is to be made to the liner. The 
label shall read "This chimney liner is for appliances that burn gas only. 
Do not connect to solid or liquid fuel-burning appliances or incinerators. " 

12.6.2 Termination. 

12.6.2.1 A chimney for residential-type or low-heat appli- 
ances shall extend at least 3 ft (0.9 m) above the highest point 
where it passes through a roof of a building and at least 2 ft 
(0.6 m) higher than any portion of a building within a hori- 
zontal distance of 10 ft (3 m). (SeeFigure 12.6.2.1.) 

12.6.2.2 A chimney for medium-heat appliances shall extend 
at least 10 ft (3 m) higher than any portion of any building 
within 25 ft (7.6 m). 

12.6.2.3 A chimney shall extend atleast5 ft (1.5 m) above the 
highest connected appliance draft hood outlet or flue collar. 

12.6.2.4 Decorative shrouds shall not be installed at the ter- 
mination of factory-built chimneys except where such shrouds 
are listed and labeled for use with the specific factory-built 
chimney system and are installed in accordance with manufac- 
turers' installation instructions. 

12.6.3 Size of Chimneys. 

12.6.3.1 The effective area of a chimney venting system serv- 
ing listed appliances with draft hoods, Category I appliances, 
and other appliances listed for use with Type B vents shall be 
in accordance with one of the following methods: 

(1) Those listed in Chapter 13. 

(2) For sizing an individual chimney venting system for a 
single appliance with a draft hood, the effective areas of 
the vent connector and chimney flue shall be not less than 
the area of the appliance flue collar or draft hood oudet 
or greater than seven times the draft hood outlet area. 

(3) For sizing a chimney venting system connected to two ap- 
pliances with draft hoods, the effective area of the chim- 
ney flue shall be not less than the area of the larger draft 
hood oudet plus 50 percent of the area of the smaller 
draft hood oudet, or greater than seven times the smaller 
draft hood outlet area. 

(4) Chimney venting systems using mechanical draft shall be 
sized in accordance with approved engineering methods. 

(5) Other approved engineering methods 

1 2.6.3.2 Where an incinerator is vented by a chimney serving 
other appliances, the gas input to the incinerator shall not be 
included in calculating chimney size, provided the chimney 
flue diameter is not less than 1 in. (25 mm) larger in equiva- 
lent diameter than the diameter of the incinerator flue oudet. 



2006 Edition 



ANSI Z223.1-85 



VENTING OF APPLIANCES 



54-85 



2 ft (0.6 m) 
minimum - 



X10ft(3m) 
or less 




10 ft (3 m) 
or less 



3 ft (0.9 m) 
minimum 



Chimney 



j*r- 



Chimney 




3 ft (0.9 m) 

minimum 



Wall or 
parapet 



(a) Termination 10 ft (3 m) or Less from Ridge, Wall, or Parapet 



More than 
10 ft (3 m) 



t> Note: No height 
above parapet 
required when 
distance from walls 



■VI 



3 ft (0.9 m) 
minimum 



Chimney 



Height above 
any roof surface 
within 10 ft (3 m) 
horizontally 



or parapet is more Chimney 




3 ft (0.9 m) 
minimum 



-I^aL tnan 10 ft (3 m). 



(b) Termination More Than 10 ft (3 m) from Ridge, Wall, or Parapet 

FIGURE 12.6.2.1 Typical Termination Locations for Chimneys and Single-Wall Metal Pipes Serving 
Residential-Type and Low-Heat Appliances. 



12.6.4 Inspection of Chimneys. 

12.6.4.1 Before replacing an existing appliance or connect- 
ing a vent connector to a chimney, the chimney passageway 
shall be examined to ascertain that it is clear and free of ob- 
structions and shall be cleaned if previously used for venting 
solid or liquid fuel-burning appliances or fireplaces. 

12.6.4.2 Chimneys shall be lined in accordance with 
NFPA211, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel- 
Burning Appliances. 

Exception: Existing chimneys shall be permitted to have their use 
continued when an appliance is replaced by an appliance of similar 
type, input rating, and efficiency. 

12.6.4.3 Cleanouts shall be examined to determine that they 
will remain tighdy closed when not in use. 

12.6.4.4 When inspection reveals that an existing chimney is 
not safe for the intended application, it shall be repaired, re- 
built, lined, relined, or replaced with a vent or chimney to 
conform to NFPA 211, Standard for Chimneys, Fireplaces, Vents, 
and Solid Fuel-Burning Appliances, and shall be suitable for the 
appliances to be attached. 

12.6.5 Chimney Serving Appliances Burning Other Fuels. 

12.6.5.1 An appliance shall not be connected to a chimney 
flue serving a separate appliance designed to burn solid fuel. 



12.6.5.2 Where one chimney serves gas appliances and liquid 
fuel-burning appliances, the appliances shall be connected 
through separate openings or shall be connected through a 
single opening where joined by a suitable fitting located as 
close as practical to the chimney. Where two or more openings 
are provided into one chimney flue, they shall be at different 
levels. Where the gas appliance is automatically controlled, it 
shall be equipped with a safety shutoff device. 

12.6.5.3* A listed combination gas- and solid fuel-burning ap- 
pliance connected to a single chimney flue shall be equipped 
with a manual reset device to shut off gas to the main burner 
in the event of sustained backdraft or flue gas spillage. The 
chimney flue shall be sized to properly vent the appliance. 

12.6.5.4 A single chimney flue serving a listed combination 
gas- and oil-burning appliance shall be sized to properly vent 
the appliance. 

12.6.6 Support of Chimneys. All portions of chimneys shall be 
supported for the design and weight of the materials employed. 
Listed factory-built chimneys shall be supported and spaced in 
accordance with the manufacturer's installation instructions. 

12.6.7 Cleanouts. Where a chimney that formerly carried flue 
products from liquid or solid fuel-burning appliances is used 
with an appliance using fuel gas, an accessible cleanout shall 
be provided. The cleanout shall have a tight-fitting cover and 



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ANSI Z223. 1-86 



be installed so its upper edge is at least 6 in. (150 mm) below 
the lower edge of the lowest chimney inlet opening. 

12.6.8 Space Surrounding Lining or Vent. 

12.6.8.1 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry chimney shall not be used to vent another appliance. 

Exception: The insertion of another liner or vent within the chimney as 
provided in this code and the liner or vent manufacturer's instructions. 

12.6.8.2 The remaining space surrounding a chimney liner, 
gas vent, special gas vent, or plastic piping installed within a 
masonry, metal, or factory-built chimney flue shall not be used 
to supply combustion air. 

Exception: Direct-vent appliances designed for installation in a solid 
fuel-burning fireplace where installed in accordance with the manufac- 
turer's installation instructions. 

12.7 Gas Vents. See 3.3.105.2. 

12.7.1 Application. The installation of gas vents shall meet the 
following requirements: 

(1) Gas vents shall be installed in accordance with the manu- 
facturer's installation instructions. 

(2) A Type B-W gas vent shall have a listed capacity not less 
than that of the listed vented wall furnace to which it is 
connected. 

(3) Vents serving Category I fan-assisted appliances shall be 
installed in accordance with the appliance manufactur- 
er's instructions and Chapter 13 or other approved engi- 
neering methods. 

(4) Gas vents installed within masonry chimneys shall be in- 
stalled in accordance with the manufacturer's installation 
instructions. Gas vents installed within masonry chimneys 
shall be identified with a permanent label installed at the 
point where the vent enters the chimney. The label shall 
contain the following language: "This gas vent is for appli- 
ances that burn gas. Do not connect to solid or liquid 
fuel-burning appliances or incinerators." 

12.7.2 Gas Vent Termination. The termination of gas vents 
shall comply with the following requirements: 

(1) A gas vent shall terminate in accordance with one of the 
following: 

(a) Gas vents that are 12 in. (300 mm) or less in size and 
located not less than 8 ft (2.4 m) from a vertical wall 
or similar obstruction shall terminate above the roof 
in accordance with Figure 12.7.2 and Table 12.7.2. 

(b) Gas vents that are over 12 in. (300 mm) in size or are 
located less than 8 ft (2.4 m) from a vertical wall or simi- 
lar obstruction shall terminate not less than 2 ft (0.6 m) 
above the highest point where they pass through the 
roof and not less than 2 ft (0.6 m) above any portion of a 
building within 10 ft (3.0 m) horizontally. 

(c) Industrial appliances as provided in 12.3.4. 

(d) Direct-vent systems as provided in 12.3.5. 

(e) Appliances with integral vents as provided in 12.3.6. 

(f) Mechanical draft systems as provided in 12.4.3. 

(g) Ventilating hoods and exhaust systems as provided in 
12.4.4. 

(2) A Type B or a Type L gas vent shall terminate at least 5 ft 
(1.5 m) in verdcal height above the highest connected 
appliance draft hood or flue collar. 



(3) 



A Type B-W gas vent shall terminate at least 12 ft (3.7 m) in 
vertical height above the bottom of the wall furnace. 
A gas vent extending through an exterior wall shall not 
terminate adjacent to the wall or below eaves or parapets, 
except as provided in 12.3.5 and 12.4.3. 
Decorative shrouds shall not be installed at the termination 
of gas vents except where such shrouds are listed for use with 
the specific gas venting system and are installed in accor- 
dance with manufacturers' installation instructions. 
All gas vents shall extend through the roof flashing, roof 
jack, or roof thimble and terminate with a listed cap or 
listed roof assembly. 
(7) A gas vent shall terminate at least 3 ft (0.9 m) above a 
forced air inlet located within 10 ft (3.0 m). 



(4) 



(5) 



(6) 



Listed — i 
cap 

Listed — 
gas vent 



Lowest discharge opening 
1 _J_ 




Roof pitch is x/12 



H (minimum) - 
Minimum height from roof 
to lowest discharge opening 



FIGURE 12.7.2 Termination Locations for Gas Vents with 
Listed Caps 12 in. (300 mm) or Less in Size at Least 8 ft (2.4 m) 
from a Vertical WkU. 



Table 12.7.2 Roof Slope Heights 





H (minimum) 


Roof Slope 


ft 


m 


Flat to 6/12 


1.0 


0.30 


Over 6/12 to 7/12 


1.25 


0.38 


Over 7/12 to 8/12 


1.5 


0.46 


Over 8/12 to 9/12 


2.0 


0.61 


Over 9/12 to 10/12 


2.5 


0.76 


Over 10/12 to 11/12 


3.25 


0.99 


Over 11/12 to 12/12 


4.0 


1.22 


Over 12/12 to 14/12 


5.0 


1.52 


Over 14/12 to 16/12 


6.0 


1.83 


Over 16/12 to 18/12 


7.0 


2.13 


Over 18/12 to 20/12 


7.5 


2.27 


Over 20/12 to 21/12 


8.0 


2.44 



12.7.3 Size of Gas Vents. Venting systems shall be sized and 
constructed in accordance with Chapter 13 or other approved 
engineering methods and the gas vent and the appliance 
manufacturer's instructions. 

12.7.3.1* Category I Appliances. The sizing of natural draft 
venting systems serving one or more listed appliances 
equipped with a draft hood or appliances listed for use with 



2006 Edition 



ANSI Z223. 1-87 



VENTING OF APPLIANCES 



54-87 



Type B gas vent, installed in a single story of a building, shall 
be in accordance with one of the following: 

(1) The provisions of Chapter 13. 

(2) Vents serving fan-assisted combustion system appliances, or 
combinations of fan-assisted combustion system and draft 
hood-equipped appliances shall be sized in accordance with 
Chapter 13 or other approved engineering methods. 

(3) For sizing an individual gas vent for a single, draft hood- 
equipped appliance, the effective area of the vent connec- 
tor and the gas vent shall be not less than the area of the 
appliance draft hood outlet or greater than seven times 
the draft hood outlet area. 

(4) For sizing a gas vent connected to two appliances, with 
draft hoods, the effective area of the vent shall be not less 
than the area of the larger draft hood outlet plus 50 per- 
cent of the area of the smaller draft hood outlet or greater 
than seven times the smaller draft hood outlet area. 

(5) Other approved engineering practices. 

12.7.3.2 Vent Offsets. Type B and Type L vents sized in accor- 
dance with item (3) or (4) of 12.7.3.1 shall extend in a gener- 
ally vertical direction with offsets not exceeding 45 degrees, 
except that a vent system having not more than one 60 degree 
offset shall be permitted. Any angle greater than 45 degrees 
from the vertical is considered horizontal. The total horizon- 
tal distance of a vent plus the horizontal vent connector serv- 
ing draft hood-equipped appliances shall not be greater than 
75 percent of the vertical height of the vent. 

12.7.3.3 Category II, Category III, and Category IV Appli- 
ances. The sizing of gas vents for Category II, Category III, and 
Category IV appliances shall be in accordance with the appli- 
ance manufacturer's instructions. 

12.7.3.4 Sizing. Chimney venting systems using mechanical 
draft shall be sized in accordance with approved engineering 
methods. 

12.7.4 Gas Vents Serving Appliances on More Than One Floor. 

12.7.4.1 A common gas vent shall be permitted in multistory 
installations to vent Category I appliances located on more 
than one floor level, provided the venting system is designed 
and installed in accordance with approved engineering meth- 
ods. For the purpose of this section, crawl spaces, basements, 
and attics shall be considered as floor levels. 

12.7.4.2 All appliances connected to the common vent shall 
be located in rooms separated from occupiable space. Each of 
these rooms shall have provisions for an adequate supply of 
combustion, ventilation, and dilution air that is not supplied 
from occupiable space. (See Figure 12. 7.4.2.) 

12.7.4.3 The size of the connectors and common segments 
of multistory venting systems for appliances listed for use 
with a Type B double-wall gas vent shall be in accordance 
with Table 13.2(a), provided all of the following apply: 

(1) The available total height (H)for each segment of a mul- 
tistory venting system is the vertical distance between the 
level of the highest draft hood outlet or flue collar on that 
floor and the centerline of the next highest interconnec- 
tion tee. [See Figure G.l(k).] 

(2) The size of the connector for a segment is determined 
from the appliance's gas input rate and available connec- 
tor rise and shall not be smaller than the draft hood outlet 
or flue collar size. 



-TvV 



Gas furnace 




Type B gas vents 



Air grilles in 
outside walls 



Louvered door could 
be used in lieu of 
outside wall grilles 



jv- 



FIGURE 12.7.4.2 Plan View of Practical Separation Method 
for Multistory Gas Venting. 



(3) The size of the common vertical vent segment, and of the 
interconnection tee at the base of that segment, is based 
on the total appliance's gas input rate entering that seg- 
ment and its available total height. 

12.7.5 Support of Gas Vents. Gas vents shall be supported and 
spaced in accordance and the manufacturer's installation in- 
structions. 

12.7.6 Marking. In those localities where solid and liquid fuels 
are used extensively, gas vents shall be permanently identified 
by a label attached to the wall or ceiling at a point where the 
vent connector enters the gas vent. The label shall read: "This 
gas vent is for appliances that burn gas. Do not connect to 
solid or liquid fuel-burning appliances or incinerators." The 
authority having jurisdiction shall determine whether its area 
constitutes such a locality. 

12.8 Single-Wall Metal Pipe. 

12.8.1 Construction. Single-wall metal pipe shall be con- 
structed of galvanized sheet steel not less than 0.0304 in. 
(0.7 mm) thick or of other approved, noncombustible, 
corrosion-resistant material. 

12.8.2* Cold Climate. Uninsulated single-wall metal pipe shall 
not be used outdoors for venting appliances in regions where 
the 99 percent winter design temperature is below 32 degrees 
Fahrenheit. 

12.8.3 Termination. The termination of single-wall metal pipe 
shall meet the following requirements: 

(1) Single-wall metal pipe shall terminate at least 5 ft (1.5 m) 
in vertical height above the highest connected appliance 
draft hood oudet or flue collar. 

(2) Single-wall metal pipe shall extend at least 2 ft (0.6 m) 
above the highest point where it passes through a roof of a 
building and at least 2 ft (0.6 m) higher than any portion 
of a building within a horizontal distance of 10 ft (3 m). 
(See Figure 12.6.2.1.) 

(3) An approved cap or roof assembly shall be attached to the 
terminus of a single-wall metal pipe. (Also see 12.8.4.3.) 



2006 Edition 



54-88 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-88 



12.8.4 Installation with Appliances Permitted by 12.5.1. 

12.8.4.1 Single-wall metal pipe shall be used only for runs 
directly from the space in which the appliance is located 
through the roof or exterior wall to the outer air. A pipe pass- 
ing through a roof shall extend without interruption through 
the roof flashing, roof jacket, or roof thimble. 

12.8.4.2 Single-wall metal pipe shall not originate in any un- 
occupied attic or concealed space and shall not pass through 
any attic, inside wall, concealed space, or floor. (For the installa- 
tion of a single-wall metal pipe through an exterior combustible wall, 
see 12.11.14,2.) 

12.8.4.3 Single-wall metal pipe used for venting an incinera- 
tor shall be exposed and readily examinable for its full length 
and shall have suitable clearances maintained. 

12.8.4.4 Minimum clearances from single-wall metal pipe to 
combustible material shall be in accordance with Table 
12.8.4.4, Reduced clearances from single-wall metal pipe to 
combustible material shall be as specified for vent connectors 
in Table 10.2.3(b). 

12.8.4.5 Where a single-wall metal pipe passes through a roof 
constructed of combustible material, a noncombustible, non- 
ventilating thimble shall be used at the point of passage. The 
thimble shall extend at least 18 in. (460 mm) above and 6 in. 
(150 mm) below the roof with the annular space open at the 
bottom and closed only at the top. The thimble shall be sized 
in accordance with 12.11.14.2. 

12.8.5 Size of Single-Wall Metal Pipe. Single-wall metal piping 
shall comply with the following requirements: 

(1)*A venting system of a single-wall metal pipe shall be sized 
in accordance with one of the following methods and the 
appliance manufacturer's instructions: 



(a) For a draft hood-equipped appliance, in accordance 
with Chapter 13 

(b) For a venting system for a single appliance with a 
draft hood, the areas of the connector and the pipe 
each shall not be less than the area of the appliance 
flue collar or draft hood outlet, whichever is smaller. 
The vent area shall not be greater than seven times 
the draft hood outlet area. 

(c) Other approved engineering methods 

(2) Where a single-wall metal pipe is used and has a shape 
other than round, it shall have an equivalent effective 
area equal to the effective area of the round pipe for 
which it is substituted and the minimum internal dimen- 
sion of the pipe shall be 2 in. (50 mm). 

(3) The vent cap or a roof assembly shall have a venting ca- 
pacity not less than that of the pipe to which it is attached. 

12.8.6 Support of Single-Wall Metal Pipe. All portions of 
single-wall metal pipe shall be supported for the design and 
weight of the material employed. 

12.8.7 Marking. Single-wall metal pipe shall comply with the 
marking provisions of 12.7.6. 

12.9* Through the Wall Vent Termination. 

12.9.1 A mechanical draft venting system shall terminate at 
least 3 ft (0.9 m) above any forced air inlet located within 10 ft 
(3 m). 

Exception No. 1: This provision shall not apply to the combustion air 
intake of a direct-vent appliance. 

Exception No. 2: This provision shall not apply to the separation of 
the integral outdoor air inlet and flue gas discharge of listed outdoor 
appliances. 



Table 12.8.4.4 Clearances for Connectors 



Minimum Distance from Combustible Material 



Appliance 



Listed Type B 
Gas Vent 
Material 


Listed Type L 
Vent Material 


Single-Wall 
Metal Pipe 


Factory-Built 
Chimney 
Sections 


As listed 


As listed 


6 in. 


As listed 


6 in. 


6 in. 


9 in. 


As listed 


Not 


As listed 


9 in. 


As listed 


permitted 








Not 


As listed 


As listed 


As listed 


permitted 
Not 


6 in. 


9 in. 


As listed 


permitted 

Not 


9 in. 


18 in. 


As listed 


permitted 
Not 


Not permitted 


36 in. 


As listed 


permitted 









Listed appliance with draft hoods and 

appliance listed for use with Type B gas 

vents 
Residential boilers and furnaces with listed gas 

conversion burner and with draft hood 
Residential appliances listed for use with 

Type L vents 
Listed gas-fired toilets 

Unlisted residential appliances with draft hood 

Residential and low-heat appliances other than 

those above 
Medium-heat appliance 



For SI units, 1 in. = 25.4 mm. 

Note: These clearances shall apply unless the installation instructions of a listed appliance or connector 

specify different clearances, in which case the listed clearances shall apply. 



2006 Edition 



ANSI Z223. 1-89 



VENTING OF APPLIANCES 



54-89 



12.9.2 A mechanical draft venting system of other than 
direct-vent type shall terminate at least 4 ft (1.2 m) below, 4 ft 
(1.2 m) horizontally from, or 1 ft (300 mm) above any door, 
operable window, or gravity air inlet into any building. The 
bottom of the vent terminal shall be located at least 12 in. 
(300 mm) above grade. 

12.9.3 The vent terminal of a direct-vent appliance with an 
input of 10,000 Btu/hr (3 kW) or less shall be located at least 
6 in. (150 mm) from any air opening into a building, and such 
an appliance with an input over 10,000 Btu/hr (3 kW) but not 
over 50,000 Btu/hr (14.7 kW) shall be installed with a 9 in. 
(230 mm) vent termination clearance, and an appliance with 
an input over 50,000 Btu/hr (14.7 kW) shall have at least a 
12 in. (300 mm) vent termination clearance. The bottom of 
the vent terminal and the air intake shall be located at least 
12 in. (300 mm) above grade. 

12.9.4 Through-the-wall vents for Category II and Category IV 
appliances and noncategorized condensing appliances shall not 
terminate over public walkways or over an area where condensate 
or vapor could create a nuisance or hazard or could be detrimen- 
tal to the operation of regulators, relief valves, or other equip- 
ment. Where local experience indicates that condensate is a 
problem with Category I and Category III appliances, this provi- 
sion shall also apply. 

12.10 Condensation Drain. 

12.10.1 Provision shall be made to collect and dispose of con- 
densate from venting systems serving Category II and Cat- 
egory IV appliances and noncategorized condensing appli- 
ances in accordance with 12.9.4. 

12.10.2 Where local experience indicates that condensation 
is a problem, provision shall be made to drain off and dispose 
of condensate from venting systems serving Category I and 
Category III appliances in accordance with 12.9.4. 

12.11 Vent Connectors for Category I Appliances. 

12.11.1 Where Required. A vent connector shall be used to 
connect an appliance to a gas vent, chimney, or single-wall 
metal pipe, except where the gas vent, chimney, or single-wall 
metal pipe is directly connected to the appliance. 

12.11.2 Materials. 

12.11.2.1 A vent connector shall be made of noncombustible, 
corrosion-resistant material capable of withstanding the vent 
gas temperature produced by the appliance and of sufficient 
thickness to withstand physical damage. 

12.11.2.2 Where the vent connector used for an appliance 
having a draft hood or a Category I appliance is located in or 
passes through an unconditioned area, that portion of the 
vent connector shall be listed Type B, Type L, or listed vent 
material having equivalent insulation qualities. 

Exception: Single-wall metal pipe located within the exterior walls of 
the building and located in areas having a local 99 percent winter 
design temperature of5°F(-15°C)or higher (see Figure G. 2. 4). 

12.11.2.3 Where the vent connector used for an appliance 
having a draft hood or a Category I appliance is located in or 
passes through attics and crawl spaces, that portion of the vent 
connector shall be listed Type B, Type L, or listed vent material 
having equivalent insulation qualities. 

12.11.2.4 Vent connectors for residential-type appliances 
shall comply with the following: 



(1) Vent connectors for listed appliances having draft hoods, 
appliances having draft hoods and equipped with listed 
conversion burners, and Category I appliances that are 
not installed in attics, crawl spaces, or other uncondi- 
tioned areas shall be one of the following: 

(a) Type B or Type L vent material 

(b) Galvanized sheet steel not less than 0.018 in. 
(0.46 mm) thick 

(c) Aluminum (1100 or 3003 alloy or equivalent) sheet 
not less than 0.027 in. (0.69 mm) thick 

(d) Stainless steel sheet not less than 0.012 in. (0.31 mm) 
thick 

(e) Smooth interior wall metal pipe having resistance to 
heat and corrosion equal to or greater than that of 
(b), (c), or (d) above 

(f) A listed vent connector 

(2) Vent connectors shall not be covered with insulation. 

Exception: Listed insulated vent connectors shall be installed accord- 
ing to the terms of their listing. 

12.11.2.5 Avent connector for a nonresidential low-heat appli- 
ance shall be a factory-built chimney section or steel pipe having 
resistance to heat and corrosion equivalent to that for the appro- 
priate galvanized pipe as specified in Table 12.11.2.5. Factory- 
built chimney sections shall be joined together in accordance 
with the chimney manufacturer's instructions. 



Table 1 2 • 1 1 . 2 • 5 Minimum Thickness for 
Galvanized Steel Vent Connectors for Low-Heat 
Appliances 



Diameter of 


Minimum 


Connector (in.) 


Thickness (in.) 


Less than 6 


0.019 


6 to less than 10 


0.023 


10 to 12 inclusive 


0.029 


14 to 16 inclusive 


0.034 


Over 16 


0.056 


For SI units, 1 in. = 25.4 mm, 1 in. 2 - 


= 645 mm 2 . 



12.11.2.6 Vent connectors for medium-heat appliances and 
commercial and industrial incinerators shall be constructed of 
factory-built, medium-heat chimney sections or steel of a 
thickness not less than that specified in Table 12.11.2.6 and 
shall comply with the following: 

(1) A steel vent connector for an appliance with a vent gas 
temperature in excess of 1000°F (538°C) measured at the 
entrance to the connector shall be lined with medium- 
duty fire brick or the equivalent. 

(2) The lining shall be at least 2V6 in. (64 mm) thick for a vent 
connector having a diameter or greatest cross-sectional 
dimension of 18 in. (460 mm) or less. 

(3) The lining shall be at least 4V£ in. (110 mm) thick laid on 
the 4 ] /2 in. (110 mm) bed for a vent connector having a 
diameter or greatest cross-sectional dimension greater 
than 18 in. (460 mm). 

(4) Factory-built chimney sections, if employed, shall be 
joined together in accordance with the chimney manufac- 
turer's instructions. 



2006 Edition 



54-90 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-90 



Table 12.11.2.6 Minimum Thickness for 
Steel Vent Connectors for Medium-Heat 
Appliances and Commercial and Industrial 
Incinerators 



Vent Connector Size 




Diameter (in.) 


Area (in. 2 ) 


Thickness (in.) 


Up to 14 
Over 14 to 16 
Over 16 to 18 

Over 18 


Up to 154 

154 to 201 

201 to 254 

Larger than 254 


0.053 
0.067 
0.093 
0.123 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 



12.11.3* Size of Vent Connector. 

12.11.3.1 A vent connector for an appliance with a single 
draft hood or for a Category I fan-assisted combustion system 
appliance shall be sized and installed in accordance with 
Chapter 13 or other approved engineering methods. 

12.11.3.2 For a single appliance having more than one draft 
hood outlet or flue collar, the manifold shall be constructed 
according to the instructions of the appliance manufacturer. 
Where there are no instructions, the manifold shall be de- 
signed and constructed in accordance with approved engi- 
neering practices. As an alternate method, the effective area of 
the manifold shall equal the combined area of the flue collars 
or draft hood outlets and the vent connectors shall have a 
minimum 1 ft (0.3 m) rise. 

12.11.3.3 Where two or more appliances are connected to a 
common vent or chimney, each vent connector shall be sized 
in accordance with Chapter 13 or other approved engineering 
methods. 

12.11.3.4 As an alternative method applicable only where all 
of the appliances are draft hood-equipped, each vent connec- 
tor shall have an effective area not less than the area of the 
draft hood outlet of the appliance to which it is connected. 

12.11.3.5 Where two or more appliances are vented through 
a common vent connector or vent manifold, the common vent 
connector or vent manifold shall be located at the highest 
level consistent with available headroom and clearance to 
combustible material and shall be sized in accordance with 
Chapter 13 or other approved engineering methods. 

12.11.3.6 As an alternate method applicable only where there 
are two draft hood-equipped appliances, the effective area of the 
common vent connector or vent manifold and all junction fit- 
tings shall be not less than the area of the larger vent connector 
plus 50 percent of the area of the smaller flue collar outlet. 

12.11.3.7 Where the size of a vent connector is increased to 
overcome installation limitations and obtain connector capac- 
ity equal to the appliance input, the size increase shall be 
made at the appliance draft hood outlet. 

12.11.4 Two or More Appliances Connected to a Single Vent. 

12.11.4.1 Where two or more vent connectors enter a common 
gas vent, chimney flue, or single-wall metal pipe, the smaller con- 
nector shall enter at the highest level consistent with the available 
headroom or clearance to combustible material. 



12.11.4.2 Vent connectors serving Category I appliances shall 
not be connected to any portion of a mechanical draft system 
operating under positive static pressure, such as those serving 
Category III or Category IV appliances. 

12.11.5 Clearance. Minimum clearances from vent connec- 
tors to combustible material shall be in accordance with 
Table 12.8.4.4. 

Exception: The clearance between a vent connector and combustible 
material shall be permitted to be reduced where the combustible material 
is protected as specified for vent connectors in Table 10.2.3(b). 

12.11.6 Avoid Unnecessary Bends. A vent connector shall be 
installed so as to avoid turns or other construction features 
that create excessive resistance to flow of vent gases. 

12.11.7 Joints. Joints between sections of connector piping 
and connections to flue collars or draft hood outlets shall be 
fastened in accordance with one of the following methods: 

( 1 ) By sheet metal screws 

(2) By vent connectors of listed vent material assembled and 
connected to flue collars or draft hood outlets in accor- 
dance with the manufacturers' instructions 

(3) By other approved means 

12.11.8 Slope. A vent connector shall be installed without any 
dips or sags and shall slope upward toward the vent or chim- 
ney at least !4 in. /ft (20 mm/m) . 

Exception: Vent connectors attached to a mechanical draft system 
installed in accordance with the manufacturers instructions. 

12.11.9 Length of Vent Connector. 

1 2. 11 .9. 1 A vent connector shall be as short as practical, and the 
appliance located as close as practical, to the chimney or vent. 

12.11.9.2 The maximum horizontal length of a single-wall 
connector shall be 75 percent of the height of the chimney or 
vent, except for engineered systems. The maximum length of 
an individual connector for a chimney or vent system serving 
multiple appliances, from the appliance outlet to the junction 
with the common vent or another connector, shall be 100 per- 
cent of the height of the chimney or vent. 

12.11.9.3 The maximum horizontal length of a Type B 
double-wall connector shall be 100 percent of the height of 
the chimney or vent, except for engineered systems. The maxi- 
mum length of an individual connector for a chimney or vent 
system serving multiple appliances, from the appliance outlet 
to the junction with the common vent or another connector, 
shall be 100 percent of the height of the chimney or vent. 

12.11.10 Support. Avent connector shall be supported for the 
design and weight of the material employed to maintain clear- 
ances and prevent physical damage and separation of joints. 

12.11.11 Chimney Connection. Where entering a flue in a ma- 
sonry or metal chimney, the vent connector shall be installed 
above the extreme bottom to avoid stoppage. Where a thimble 
or slip joint is used to facilitate removal of the connector, the 
connector shall be firmly attached to or inserted into the 
thimble or slip joint to prevent the connector from falling out. 
Means shall be employed to prevent the connector from en- 
tering so far as to restrict the space between its end and the 
opposite wall of the chimney flue. 

12.11.12 Inspection. The entire length of a vent connector shall 
be readily accessible for inspection, cleaning, and replacement. 



2006 Edition 



ANSI Z223. 1-91 



VENTING OF APPLIANCES 



54-91 



12.11.13 Fireplaces. Avent connector shall not be connected 
to a chimney flue serving a fireplace unless the fireplace flue 
opening is permanently sealed. 

12.11.14 Passage Through Ceilings, Floors, or Walls. 

12.11.14.1 Single-wall metal pipe connectors shall not pass 
through any wall, floor, or ceiling except as permitted by sec- 
tions 12.8.4.1 and 12.11.14.2. 

12.11.14.2 Avent connector made of a single-wall metal pipe 
shall not pass through a combustible exterior wall unless 
guarded at the point of passage by a ventilated metal thimble 
not smaller than the following: 

(1) For listed appliances with draft hoods and appliances 
listed for use with Type B gas vents, the thimble shall be a 
minimum of 4 in. (100 mm) larger in diameter than the 
vent connector. Where there is a run of not less than 6 ft 
(1.8 m) of vent connector in the opening between the 
draft hood outlet and the thimble, the thimble shall be a 
minimum of 2 in. (50 mm) larger in diameter than the 
vent connector. 

(2) For unlisted appliances having draft hoods, the thimble 
shall be a minimum of 6 in. (150 mm) larger in diameter 
than the vent connector. 

(3) For residential and low-heat appliances, the thimble shall 
be a minimum of 12 in. (300 mm) larger in diameter than 
the vent connector. 

Exception: In lieu of thimble protection, all combustible material in 
the wall shall be removed from the vent connector a sufficient distance 
to provide the specified clearance from such vent connector to combus- 
tible material. Any material used to close up such opening shall be 
noncombustible. 

12.11.14.3 Vent connectors for medium-heat appliances shall 
not pass through walls or partitions constructed of combus- 
tible material. 

12.12 Vent Connectors for Category II, Category III, and Cat- 
egory IV Appliances. See Section 12.5. 

12.13 Draft Hoods and Draft Controls. 

12.13.1 Appliances Requiring Draft Hoods. Vented appli- 
ances shall be installed with draft hoods. 

Exception: Dual oven-type combination ranges, incinerators, direct- 
vent appliances; fan-assisted combustion system appliances; appli- 
ances requiring chimney draft for operation; single-firebox boilers 
equipped with conversion burners with inputs greater than 400,000 
Btu/hr (11 7 kW); appliances equipped with blast, power, or pressure 
burners that are not listed for use with draft hoods; and appliances 
designed for forced venting. 

12.13.2 Installation. A draft hood supplied with or forming a 
part of a listed vented appliance shall be installed without al- 
teration, exactly as furnished and specified by the appliance 
manufacturer. 

12.13.2.1 If a draft hood is not supplied by the appliance 
manufacturer where one is required, a draft hood shall be 
installed, be of a listed or approved type, and, in the absence 
of other instructions, be of the same size as the appliance flue 
collar. Where a draft hood is required with a conversion 
burner, it shall be of a listed or approved type. 

12.13.2.2 Where it is determined that a draft hood of special 
design is needed or preferable for a particular installation, the 
installation shall be in accordance with the recommendations 



of the appliance manufacturer and shall be with the approval 
of the authority having jurisdiction. 

12.13.3 Draft Control Devices. Where a draft control device is 
part of the appliance or is supplied by the appliance manufac- 
turer, it shall be installed in accordance with the manufacturer's 
instructions. In the absence of manufacturer's instructions, the 
device shall be attached to the flue collar of the appliance or as 
near to the appliance as practical. 

12.13.4* Additional Devices. Appliances (except incinerators) 
requiring controlled chimney draft shall be permitted to be 
equipped with listed double-acting barometric draft regula- 
tors installed and adjusted in accordance with the manufactur- 
ers' instructions. 

12.13.5 Location. Draft hoods and barometric draft regulators 
shall be installed in the same room or enclosure as the appliance 
in such a manner as to prevent any difference in pressure be- 
tween the hood or regulator and the combustion air supply. 

12.13.6 Positioning. Draft hoods and draft regulators shall be 
installed in the position for which they were designed with 
reference to the horizontal and vertical planes and shall be 
located so that the relief opening is not obstructed by any part 
of the appliance or adjacent construction. The appliance and 
its draft hood shall be located so that the relief opening is 
accessible for checking vent operation. 

12.13.7 Clearance. A draft hood shall be located so that its 
relief opening is not less than 6 in. (150 mm) from any surface 
except that of the appliance it serves and the venting system to 
which the draft hood is connected. Where a greater or lesser 
clearance is indicated on the appliance label, the clearance 
shall not be less than that specified on the label. Such clear- 
ances shall not be reduced. 

12.14 Manually Operated Dampers. A manually operated 
damper shall not be placed in any appliance vent connector. 
Fixed baffles shall not be classified as manually operated 
dampers. 

12.15 Automatically Operated Vent Dampers. An automati- 
cally operated vent damper shall be of a listed type. 

12.16 Obstructions. Devices that retard the flow of vent gases 
shall not be installed in a vent connector, chimney, or vent. 
The following shall not be considered as obstructions: 

(1) Draft regulators and safety controls specifically listed for 
installation in venting systems and installed in accordance 
with the manufacturer's installation instructions. 

(2) Approved draft regulators and safety controls designed 
and installed in accordance with approved engineering 
methods. 

(3) Listed heat reclaimers and automatically operated vent 
dampers installed in accordance with the manufacturers' 
installation instructions. 

(4) Vent dampers serving listed appliances installed in accor- 
dance with 13.1.1 and 13.2.1 or other approved engineer- 
ing methods. 

(5) Approved economizers, heat reclaimers, and recuperators 
installed in venting systems of appliances not required to be 
equipped with draft hoods, provided the gas utilization ap- 
pliance manufacturer's instructions cover the installation of 
such a device in the venting system and performance in ac- 
cordance with 12.1 and 12.4.1 is obtained. 



2006 Edition 



54-92 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-92 



Chapter 13 Sizing of Category I Venting Systems 

13.1 Additional Requirements to Single Appliance Vent. 

13.1.1 Obstructions and Vent Dampers. Venting Table 13.1 (a) 
through Table 13.1(f) shall not be used where obstructions 
(see Section 12.16) are installed in the venting system. The in- 
stallation of vents serving listed appliances with vent dampers 
shall be in accordance with the appliance manufacturer's in- 
structions or in accordance with the following: 

(1) The maximum capacity of the vent system shall be deter- 
mined using the "NAT Max" column. 

(2) The minimum capacity shall be determined as though the 
appliance were a fan-assisted appliance, using the "FAN 
Min" column to determine the minimum capacity of the 
vent system. Where the corresponding "Fan Min" is "NA," 
the vent configuration shall not be permitted and an al- 
ternative venting configuration shall be utilized. 

13.1.2 Vent Downsizing. Where the vent size determined from 
the tables is smaller than the appliance draft hood outlet or flue 
collar, the use of the smaller size shall be permitted, provided 
that the installation complies with all of the following require- 
ments: 

(1) The total vent height (H) is at least 10 ft (3 m). 

(2) Vents for appliance draft hood outlets or flue collars 12 in. 
(300 mm) in diameter or smaller are not reduced more 
than one table size. 

(3) Vents for appliance draft hood oudets or flue collars 
larger than 12 in. (300 mm) in diameter are not reduced 
more than two table sizes. 

(4) The maximum capacity listed in the tables for a fan-assisted 
appliance is reduced by 10 percent (0.90 x maximum table 
capacity) . 

(5) The draft hood outlet is greater than 4 in. (100 mm) in 
diameter. A 3 in. (80 mm) diameter vent shall not be con- 
nected to a 4 in. (100 mm) diameter draft hood outlet. 
This provision shall not apply to fan-assisted appliances. 

13.1.3 Elbows. Single-appliance venting configurations with 
zero (0) lateral lengths in Table 13.1(a), Table 13.1(b), and 
Table 13.1(e) shall not have elbows in the venting system. 
Single-appliance venting with lateral lengths include two 
90 degree elbows. For each additional elbow up to and includ- 
ing 45 degrees, the maximum capacity listed in the venting 
tables shall be reduced by 5 percent. For each additional el- 
bow greater than 45 degrees up to and including 90 degrees, 
the maximum capacity listed in the venting tables shall be re- 
duced by 10 percent. 

13.1.4 Zero Lateral. Zero (0) lateral (L) shall apply only to a 
straight vertical vent attached to a top outlet draft hood or flue 
collar. 

13.1.5 High Altitude Installations. Sea level input ratings shall 
be used when determining maximum capacity for high-altitude 
installation. Actual input (derated for altitude) shall be used for 
determining minimum capacity for high-altitude installation. 

13.1.6 Two Stage/Modulating Appliances. For appliances with 
more than one input rate, the minimum vent capacity (FAN 
Min) determined from the Chapter 13 tables shall be less than 
the lowest appliance input rating, and the maximum vent ca- 
pacity (FAN Max/NAT Max) determined from the tables shall 
be greater than the highest appliance rating input. 

13.1.7* Corrugated Chimney Liners. Listed corrugated metal- 
lic chimney liner systems in masonry chimneys shall be sized by 



using Table 13.1 (a) or Table 13.1 (b) for Type B vents, with the 
maximum capacity reduced by 20 percent (0.80 x maximum ca- 
pacity) and the minimum capacity as shown in Table 13.1(a) or 
Table 13.1(b). Corrugated metallic liner systems installed with 
bends or offsets shall have their maximum capacity further re- 
duced in accordance with 13.1.3. The 20 percent reduction for 
corrugated metallic chimney liner systems includes an allowance 
for one long radius 90 degree turn at the bottom of the liner. 

13.1.8 Connection to Chimney Liners. Connections between 
chimney liners and listed double-wall connectors shall be 
made with listed adapters designed for such purpose. 

1 3. 1 .9 Vertical Vent Upsizing/7 x Rule. Where the vertical vent 
has a larger diameter than the vent connector, the vertical vent 
diameter shall be used to determine the minimum vent capacity, 
and the connector diameter shall be used to determine the maxi- 
mum vent capacity. The flow area of the vertical vent shall not 
exceed seven times the flow area of the listed appliance catego- 
rized vent area, flue collar area, or draft hood outlet area unless 
designed in accordance with approved engineering methods. 

13.1.10 Draft Hood Conversion Accessories. Draft hood con- 
version accessories for use with masonry chimneys venting 
listed Category I fan-assisted appliances shall be listed and in- 
stalled in accordance with the listed accessory manufacturers' 
installation instructions. 

13.1.11 Chimneys and Vent Locations. Table 13.1(a) through 
Table 13.1 (e) shall be used only for chimneys and vents not ex- 
posed to the outdoors below the roof line. A Type B vent or listed 
chimney lining system passing through an unused masonry 
chimney flue shall not be considered to be exposed to the out- 
doors. A Type B vent passing through an unventilated enclosure 
or chase insulated to a value of not less than R8 shall not be 
considered to be exposed to the outdoors. Table 13.1(c) in com- 
bination with Table 13.1(f) shall be used for clay-tile-lined exte- 
rior masonry chimneys, provided all of the following require- 
ments are met: 

(1) The vent connector is Type B double wall. 

(2) The vent connector length is limited to 18 in./in. (18 mm/ 
mm) of vent connector diameter. 

(3) The appliance is draft hood-equipped. 

(4) The input rating is less than the maximum capacity given 
in Table 13.1(c). 

(5) For a water heater, the outdoor design temperature shall 
not be less than 5°F (-15X) . 

(6) For a space-heating appliance, the input rating is greater 
than the minimum capacity given by Table 13.1 (f). 

(7) Where the conditions of 13.1.11(1) through (6) cannot 
be met, an alternative venting design shall be used, such 
as a listed chimney lining system. 

Exception: Vents sewing listed appliances installed in accordance 
with the appliance manufacturer's installation instructions. 

13.1.12 Corrugated Vent Connector Size. Corrugated vent 
connectors shall not be smaller than the listed appliance cat- 
egorized vent diameter, flue collar diameter, or draft hood 
outlet diameter. 

13.1.13 Upsizing. Vent connectors shall not be upsized more 
than two sizes greater than the listed appliance categorized vent 
diameter, flue collar diameter, or draft hood oudet diameter. 



2006 Edition 



ANSI Z223. 1-93 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-93 



13.1.14 Multiple Vertical Vent Sizes. In a single run of vent or 
vent connector, more than one diameter and type shall be 
permitted to be used, provided that all the sizes and types are 
permitted by the tables. 

13.1.15 Interpolation. Interpolation shall be permitted in cal- 
culating capacities for vent dimensions that fall between table 
entries. (See Example 3, Annex G.) 



13.1.16 Extrapolation. Extrapolation beyond the table entries 
shall not be permitted. 

13.1.17 Sizing Vents Not Covered by Tables. For vent heights 
lower than 6 ft (1.8 m) and higher than shown in the Chapter 
13 tables, engineering methods shall be used to calculate vent 
capacities. 



Table 1 3. 1 (a) Type B Double-Wall Gas Vent 





Lateral 
L 

(ft) 




















Number of Appliances: 


Single 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Connected Directly to Vent 






















Vent Diameter - 


-0(in.) 




















i 


4 


5 


6 


7 


8 


9 


















Appliance Input Rating 


n Thousands of But per Hour 
















Height 
H 

(ft) 


FAN 


■NAT 
Max 


FAN 


-NAT 
Max 


FAN 


NAT 

Mai 


FAN 




NAT 
Max 


FAN 


NAT 
Max 


FAN 


NAT 
Max 


FAN 1 


NAT 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max 


Min Max 


Min 


Max 


Min 


Max ' 


Max 


6 








78 


4.. 





152 


• ; 80 





251 


1-11 





375 


205 


524 


285 





698 J 


370 





897 


470 




2 


13 


51 


.36 


18 


97 


67 


27 


157 


105 


32 


232 


157 


44 321 


217 


53 


425 J 


285 


63 


543 


370 




4 


21 


49 


34 


30 


94 


. 64 


39 


153 


103 


50 


227 


- 153" 


66 316 


. 211. 


79 


419 } 


279 


93 


536 ; 


S62 




6 


25 


4b 


32 


36 


91 


61 


47 


149 


100 


59 


223 


149 


78 310 


205 


93 


413 | 


273 


110 


530 ! 


354 


8 








84 


: ■' 50 





165 


94. 





276 


155 





415 


Bsj 


583 


* 320 





780 [ 


415 





1006 1 


537 




2 


12 


57 


. 40 


16 


109 


75 


25 


178 


120. 


28 


263 


ISO 


42 365 


247 


50 


483 i 


322 


60 


619 


418 




5 


23 


53 


ii:SB 


32 


103 


: 71 


42 


171 


115 


53 


255 


173 


70 356 


237 


83 


473 i 


313 


99 


607 ; 


407 




8 


28 


49 


35 


39 


98 


66 


51 


164 


109 


64 


247 


It.". 


84 347 


227 


99 


463 ; 


303 


117 


596 . 


396 


10 








88 


■53 





175 


100 





295 


166 





447 


2.. 5 


631 


345 





847 i 


450 





1096 ' 


585 




2 


12 


61 


42 


17 


118 


81 


23 


194 


129 


26 


289 


*195 


40 402 


273 


48 


533 


355 


57 


684 ' 


457 




5 


23 


57 


40 


32 


113 


77 


41 


187 


124 


52 


280 


188 


68 392 


263 


81 


522 


346 


95 


671 ; 


446 




10 


30 


51 


36 


41 


104 


70 


54 


176 


115 


67 


267 


17.'. 


88 376 


245 


104 


504 ■ 


330 


122 


651 i 


427 


15 








94 


H8 





191 


112 





327 


J 87 





502 


285 


716 


S 390 J 





970 ! 


525 





1263 | 


682 




2 


11 


69 


48 


15 


136 


93 


20 


226 


150 


22 


339 


'225 


38 475 


316 


45 


633 ! 


414 


53 


815 


544 




5 


22 


65 


rt 45 


30 


130 


87. 


39 


219 


142 


49 


330 


217 


64 463 


300 


76 


620 j 


403 


90 


800 ; 


529 




10 


29 


59 


■ 41 


40 


121 


82 


51 


206 


' 135" 


64 


315 


208 


84 445 


288' 


99 


600 ! 


386 


116 


777 \ 


507 




15 


35 


53 


■ 37 


48 


112 


76 


61 


195 


128 


76 


301 


J198 


98 429 


275 


115 


580 ; 


373 


134 


755 j 


491 


20 








97 


61 





202 


119 





349 


202 





540 


307 


776 


430 





1057 ' 


575 





1384 


752 




2 


10 


75 


■51 


14 


149 


100 


18 


250 


I6S 


20 


377 


7„J 


33 531 


, 346 


41 


711 | 


470 


50 


917 j 


612 




5 


21 


71 


■,'5-48 


29 


143 


96 


38 


242 


: ' 160 


47 


367 


241 


62 519 


337 


73 


697 


460 


86 


902 ! 


599 




10 


28 


64 


~ : 44 


38 


133 


89 


50 


229 


150 


62 


351 


228 


81 499 


321 


95 


675 ] 


443 


112 


877 ' 


576 




15 


34 


58 


40 


46 


124 


. 84' 


59 


217 




73 


337 


217 


94 481 


308 


111 


654 ! 


427 


129 


853 1 


557 




20 


48 


52 


35 


55 


116 


1 78 


69 


206 


134 


84 


322 


206 


107 464 


295 


125 


634 1 


410 


145 


830 : 


537 


30 








100 


64 





213 


128" 





374 


iin 





587 


336 


853 


475' 





U73 ! 


650 





1548 ' 


855 




2 


9 


81 


.56 


13 


166 


. 112 


14 


283 


185 


18 


432 


280 


27 613 


394 


33 


826 i 


535 


42 


1072 i 


700 




5 


21 


77 


54 


28 


160 


f'108. 


36 


275 


176 


45 


421 


273 


58 600 


■ 


69 


811 : 


524 


82 


1055 1 


688 




10 


27 


70 


- 50 


37 


150 


102 


48 


262 


171 


59 


405 


261 


77 580 


371 


91 


788 


507 


107 


1028 


668 




15 


33 


64 


N\ 


44 


141 


< 96 


57 


249 


. i§S s 


70 


389 


249 


90 560 


..: 35 7f: 


105 


765 1 


490 


124 


1002 ; 


648 




20 


56 


58 


NA 


53 


132 


90 


66 


237 


154 


80 


374 


237 


102 542 


• 343 


119 


743 


473 


139 


977 ! 


628 




30 


NA 


NA 


.NA 


73 


113 


NA 


88 


214 


NA 


104 


346 


219 


131 507 


321 


149 


702 


444 


171 


929 ; 


594 


50 








101 


67 





216 


134 





397 


232 





633 


363 


932 


518* 





1297 1 


708 





1730 ' 


952 




2 


8 


86 


61 


11 


183 


122 


14 


320 




15 


497 


314 


22 715 


, .445; 


26 


975 | 


615 


33 


1276 ! 


813 




5 


20 


82 


NA 


27 


177 


119 


35 


312 


200 


43 


487 


"308 


55 702 


'' 438* 


65 


960 ! 


605 


77 


1259 1 


798 




10 


26 


76 


NA 


35 


168 


114 


45 


299 


IS), 


56 


471 


298 


73 681 


426 


86 


935 i 


589 


101 


1230 


773 




15 


59 


70 


MA 


42 


158 


NA 


54 


287 




66 


455 


•288 


85 662 


. : -412fc 


100 


911 ! 


572 


117 


1203 , 


747 




20 


NA 


NA 


NA 


50 


149 


NA 


63 


275 


169 


76 


440 


278 


97 642 


401 


113 


888 


556 


131 


1176 


722 




30 


NA 


NA 




69 


131 


NA 


84 


250 


.■■". 


99 


410 


,;.?59. 


123 605 


'. • 376 i 


141 


844 


522 


161 


1125 ; 


670 


100 





NA 


NA 


rNA 





218 


NA; 





407 


NA 





665 


400 


997 


560 





1411 


770 





1908 


1040 




2 


NA 


NA 


NA 


10 


194 


N'A 


12 


354 


\\ 


13 


566 


375 


18 831 


5 510 


21 


1155 


700 


25 


1536 


935 




5 


NA 


NA 


NA 


26 


189 


NA 


33 


347 


NA 


40 


557 


369 


52 820 


504 


60 


1141 


692 


71 


1519 


926 




10 


NA 


NA 


NA 


33 


182 


NA 


43 


335 


. 


53 


542 


361 


68 801 


,i 493 


80 


1118 


679 


94 


1492 ! 


910 




15 


NA 


NA 


NA 


40 


174 


NA 


50 


321 


NA 


62 


528 


"353 


80 782 


" 482 


93 


1095 ' 


666 


109 


1465 


895 




20 


NA 


NA 


.NA 


47 


166 


NA 


59 


311 


NA, 


71 


513 


344 


90 763 


471 


106 


1073 


653 


122 


1438 


880 




30 


NA 


NA 


';NA 


NA 


NA 


NA 


78 


290 




92 


483 


NA 


115 726 


■ 449 


131 


1029 


627 


149 


1387 


849 




50 


NA 


NA 


NA 


NA 


NA 


, NA, 


NA 


NA 


NA 


147 


428 


'"NA 


180 651 


405 


197 


944 


575 


217 


1288 ' 


787 



(continues) 



2006 Edition 



54-94 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-94 



Table 13.1(a) Continued 























Number of Appl 


ances: 


Single 










Appliance 


Type: 


Category I 




Appliance Vent Connection: 


Connected Directly to Vent 




Vent Diameter — D (in.) 




10 


12 


14 


16 


18 


20 


22 


24 
















Appliance Input Rating in 


Thousands of Btu per 


lour 














Height Lateral 


FAN JNAT' 


FAN NAT 


FAN 


NAT 

Max 


FAN 


NAT 


FAN ; NAT 


FAN NAT 


FAN 


NAT 


FAN 


NAT' 


(Ft) (ft) 


Mill 


Max Max 


Min 


Max Max 


Min 


Max 


Min 


Max 


Min 


Max . Max 


Min 


Max p Max 


Min Max 


Max 


Min 


Max 


.Max 


6 





1121 570 





1645 850 





2267 


1170 





2983 


1530 





3802 1960 





4721 2430 


5737 







6853 


3520 


2 


75 


675 • 455 


103 


982 650 


138 


1346 


890 


178 


1769 


1170 


225 


2250 1480 


296 


2782 1850 


360 3377 


2220 


426 


4030 


2670 


4 


110 


668 445 


147 


975 640 


191 


1338 


880 


242 


1761 


1,160 


300 


2242 1475 


390 


2774 1S35 


469 3370 


2215 


555 


4023 


2660 


6 


128 


661 435 


171 


967 630 


219 


1330 


870 


276 


1753 


"USD 


341 


2235 1470 


437 


2767 1820 


523 3363 


22)0 


618 


4017 


2050 


8 





1261 660 





1858 970 





2571 


1370 





3399 


1740 





4333 2220 





5387 2750 


6555 


3360 





7838 


4010 


2 


71 


770 , 515 


98 


1124 745 


130 


1543 


1020 


168 


2030 


4340 


212 


2584 1700 


278 


3196 , 2110 


336 3882 


.2561). 


401 


4634 


'11 1, 11 


5 


115 


758 50S 


154 


1110 733 


199 


1528 


1010 


251 


2013 


1330 


311 


2563 • 1685 


398 


3180 2090 


476 3863 


2545 


562 


4612 


3040 


8 


137 


746 490 


180 


1097 720 


231 


1514 


MOO 


289 


2000 


'1320' 


354 


2552 j 1670 


450 


3163 ' 2070 


537 3850 


2; 10 

,r;:'S. 


630 


4602 


3030 


10 





1377 720 





2036 1060 





2825 


1450 





3742 


1925 





4782 2450 





5955 ■ 3050 


7254 


5710 





8682 


4460 


2 


68 


852 560 


93 


1244 850 


124 


1713 


1130 


161 


2256 


1480 


202 


2868 f 1890 


264 


3556 2340 


319 4322 


28 in 


378 


5153 


3390 


5 


112 


839 547 


149 


1229 829 


192 


1696 


1105 


243 


2238 


1,461 


300 


2849 1871 


382 


3536 ' 2318 


458 4301 


2818 


540 


5132 


"' 71 


10 


142 


817 525 


187 


1204 795 


238 


1669 


1030 


298 


2209 


1 }80 


364 


2818 1840 


459 


3504 2280 


546 4268 


J7MJ 


641 


5099 


3340 


15 





1596 . 840' 





2380 1240 





3323 


i 720 





4423 


2270. 





5678 2900 





7099 3620 


8665 


4411/ 





10,393 


5300 


2 


63 


1019 ( 675 


86 


1495 985 


114 


2062 


1350 


147 


2719 


1770 


186 


3467 2260 


239 


4304 2800 


290 5232 


3410 


346 


6251 


1080 


5 


105 


1003 | 660 


140 


1476 -967 


182 


2041 


1327 


229 


2696 


1748 


283 


3442 2235 


355 


4278 2777 


426 5204 


3,1/ 


501 


6222 


4057 


10 


135 


977 635 


177 


1446 930 


227 


2009 


1289 


283 


2659 


1712 


346 


3402 i 2193 


432 


4234 2739 


510 5159 


3343 


599 


6175 


4019 


15 


155 


953 > 610" 


202 


1418 ' 905 


257 


1976 


1,250 


318 


2623 


1675 


385 


3363 2150 


479 


4192 j 2700 


564 5115 


3300 


665 


6129 


3980 


20 





1756 930 





2637 1350 





3701 


1900 





4948 


2520 





6376 3250 





7988 ; 4060 


9785 


I-,.,, 





11,753 


■V..1I1U 


2 


59 


1150 755 


81 


1694 1100 


107 


2343 


1520 


139 


3097 i 2000 


175 


3955 2570 


220 


4916 S20() 


269 5983 


Mill 


321 


7154 


1700 


5 


101 


1133 738 


135 


1674 1079 


174 


2320 


1498 


219 


3071 ' 1978 


270 


3926 2544 


337 


4885 3174 


403 5950 


3'880 


475 


7119 


4662 


10 


130 


1105 J 710 


172 


1641 '1045 


220 


2282 


1460 


273 


3029 ' 1940 


334 


3880 ; 2500 


413 


4835 1 3130 


489 5896 


3830 


573 


7063 


4600 


15 


150 


1078 688 


195 


1609 1018 


248 


2245 


1 125 


306 


2988 1910 


372 


3835 • 2465 


459 


4786 1090 


541 5844 


.3795: 


631 


7007 


4575 


20 


167 


1052 ; 665 


217 


1578 "990 


273 


2210 


1390 


335 


2948 ' 1880 


404 


3791 li'SO 


495 


4737 ; 3050 


585 5792 


3760 


689 


6953 


4550 


30 





1977 1060 





3004 1550 





4252 


2170 





5725 . ' 2920 





7420 3770 





9341 ! 4750 


011,483 


if ,ll 





13,848 


7060 


2 


54 


1351 i"865 


74 


2004 -1310 


98 


2786 


1800 


127 


3696 ! 2380 


159 


4734 3050 


199 


5900 3810 


241 7194 i 4650 


285 


8617 


5600 


5 


96 


1332 851 


127 


1981 1289 


164 


2759 


1775 


206 


3666 ; 2350 


252 


4701 . 3020 


312 


5863 ■ 3783 


373 7155 


=4622; 


439 


8574 


5552 


10 


125 


1301 829 


164 


1944 1254 


209 


2716 


17S3 


259 


3617 ' 2300 


316 


4647 2970 


386 


5803 i 3739 


456 7090 i 4574 


535 


8505 


5471 


15 


143 


1272 ' 807 


187 


1908 1220 


237 


2674 


1692 


292 


3570 2250 


354 


4594 2920 


431 


5744 3695 


507 7026 


4527 


590 


8437 


5391 


20 


160 


1243 784 


207 


1873 1185 


260 


2633 


1650 


319 


3523 ' "2200 


384 


4542 2870 


467 


5686 3650 


548 6964 


1480 


639 


8370 


5310 


30 


195 


1189 i-745 


246 


1807 1130 


305 


2555 


.1585 


369 


3433 ' 2130 


440 


4442 2785 


540 


5574 3565 


635 6842 


4375 


739 


8239 


6225 


50 





2231 [1195 





3441 1825 





4934 


i:550 





6711 f'3440 





8774 4460 


11,129 , 5635 


13,767 


15940 





16,694 


8431 


2 


41 


1620 '1010 


66 


2431 1513 


86 


3409 


2125 


113 


4554 } 2840 


141 


5864 , 3670 


171 


7339 4630 


209 8980 


V.-I5 


251 


10,788 


6860 


5 


90 


1600 996 


118 


2406 1495 


151 


3380 


2102 


191 


4520 j 2813 


234 


5826 t 3039 


283 


7295 ' 4597 


336 8933 


5654 


394 


10,737 


6818 


10 


118 


1567 | 972 


154 


2366 1466 


196 


3332 


2064 


243 


4404 | 2767 


295 


5763 '3585 


355 


7224 i 4542 


419 8855 


5585 


491 


10.652 


6749 


15 


136 


1536 948 


177 


2327 1437 


222 


3285 


2026 


274 


4409 '..2721 


330 


5701 . -3534 


396 


7155 4511 


465 8779 


5546 


542 


10,570 


1 .111 


20 


151 


1505 '924 


195 


2288 1408 


244 


3239 


1987 


300 


4356 ; 2675 


361 


5641 3481 


433 


7086 j 4479 


506 8704 


J506 


586 


10,488 


5670 


30 


183 


1446 876 


232 


2214 1S49 


287 


3150 


1910 


347 


4253 2631 


412 


5523 ' 3431 


494 


6953 4421 


577 8557 


5444 


672 


10,328 


6603 


100 





2491 il3l0 





3925 '2050 





5729 


, 150 





7914 


4050 





10,485 , 5300 


13,454 ' 6700 


016,817 


8600 





20,578 10,300 


2 


30 


1975 1170 


44 


3027 1820 


72 


4313 


.■:•:" 


95 


5834 


1500 


120 


7591 , 4600 


138 


9577 ' 5800 


169 11,803 


721 in 


204 


14.264 


8800 


5 


82 


1955 1159 


107 


3002 1803 


136 


4282 


'-•ill 


172 


5797 


3475 


208 


7548 ' 4566 


245 


9528 ,' 5769 


293 11,748 


7162 


341 


14,204 


8756 


10 


108 


1923 1142 


142 


2961 1775 


180 


4231 


2500 


223 


5737 


,3434 


268 


7478 i 4509 


318 


9447 5717 


374 11,658 


7100 


436 


14,105 


868 S 


15 


126 


1892 1124 


163 


2920 1747 


206 


4182 


•; (i>9 


252 


5678 


339 


304 


7409 ■ 4451 


358 


9367 ' 5665 


418 11,569 


7037 


487 


14,007 


8610 


20 


141 


1861 jll07 


181 


2880 '1719 


226 


4133 


2438 


277 


5619 


3351 


330 


7341 ! 4394 


387 


9289 ! 5613 


45211,482 


6975 


523 


13,910 


8537 


30 


170 


1802 1071 


215 


2803 1663 


265 


4037 


2375 


319 


5505 


)267 


378 


7209 4279 


446 


9136 ; 5509 


51411,310 


6850 


592 


13,720 


'8391 


50 


241 


1688 100O 


292 


2657 1550 


350 


3856 


2250 


415 


5289 


-3100 


486 


6956 "4050 


572 


8841 I 5300 


659 10,979 


i .r..jil 


752 


13,354 


8100 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in. 2 = 645 mm 2 . 



(Sheet 2 of 2) 



2006 Edition 



ANSI Z223.1-95 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-95 



Table 13. 1 (b) Type B Double-Wall Vemt 





Lateral 
L 
(ft) 


















Number of Appliances: 


Sing 


e 
















Appliance Type: 


Category I 




Appliance Vent Connection: 


Sing! 


e Wall Metal Connector 






























Vent Diameter 


— Z>(in.) 






















3 


4 


5 


6 


7 


8 


9 


10 


12 




















Appliance Input Rating in Thousands of Btu per 


-lour 
















Height 


FAN 


NAT 


FAN 


NAT 

Max 


FAN 


'NAT 
.Max 


FAN InAt" 


FAN 


NAT 

Max 


FAN 


NAT 

MjBC 


FAN 


NAT 
Max 


FAN 


NAT 
Max 


FAN 


NAT 


(ft) 


Min 


Max 


Mm Max 


Min 


Max 


Min 


Max j.Ma0 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max 


Max 


6 





38 


77 


45". 


59 151 


85 


85 


249 


140 


126 


373 : 204 


165 


522 


284 


211 


695 


369 


267 


894 


469 


371 


1118 


569 


537 


1639 


849 




2 


39 


51 


36 


60 96 


66 


85 


156 


|,104 


123 


231 • 156 


159 


320 


213 


201 


423 


284 


251 


541 


368 


347 


673 


453 


498 


979 


648 




4 


NA 


NA 


33- 


74 92 


63 


102 


152 


102 


146 


225 152 


187 


313 


208 


237 


416 


277 


295 


533 


360 


409 


664 


443 


584 


971 


638 




6 


NA 


NA 


31 


83 89 


60 


114 


147 


. 99 


163 


220 , 148, 


207 


307 


203 


263 


409 


271 


327 


526 


352 


449 


656 


433 


638 


962 


627 


8 





37 


83 


50 


58 164 


93 


83 


273 


154 


123 


412 ■ 284 


161 


580 


319 


206 


777 i 414 


258 


1002 


536 


360 


1257 


658 


521 


1852 


967 




2 


39 


56 


39, 


59 108 


■75 


83 


176 


119 


121 


261 ■ 179 


155 


363 


246 


197 


482 


321 


246 


617 


417 


339 


768 


513 


486 


1120 


743 




5 


NA 


NA 


■ -37': 


77 102 


69 


107 


168 


• 114 


151 


252 171 ■ 


193 


352 


235 


245 


470 


311 


305 


604 


404 


418 


754 


500 


598 


1104 


730 




8 


NA 


NA 


33, 


90 95 


'64 


122 


161 


107 


175 


243 163 


223 


342 


225 


280 


458 


300 


344 


591 


392 


470 


740 


486 


665 


1089 


715 


10 





37 


87 


53 


57 174 


"99 


82 


293 


165" 


120 


444 ! 25? 


158 


628 


344 


202 


844 


449 


253 


1093 


584 


351 


1373 


718 


507 


2031 


1057 




2 


39 


61 


41: 


59 117 


"80 


82 


193 


128 


119 


287 , 194: 


153 


400 


272 


193 


531 


354 


242 


681 


456 


332 


849 


559 


475 


1242 


848 




5 


52 


56 


39 


76 111 


.76. 


105 


185 


122 


148 


277 ) 186; 


190 


388 


261 


241 


518 


344 


299 


667 


443 


409 


834 


544 


584 


1224 


825 




10 


NA 


NA 


34 


97 100 


68 


132 


171 


112 


188 


261 ; m 


237 


369 


241 


296 


497 


325 


363 


643 


423 


492 


808 


520 


688 


1194 


788 


15 





36 


93 


:..-57J 


56 190 


.;bi 


80 


325 


, 186 


116 


499 1 288i 


153 


713 


388 


195 


966 


,523 


244 


1259 


681 


336 


1591 


838 


488 


2374 


1237 




2 


38 


69 


47 


57 136 


93 


80 


225 


149 


115 


337 : 224 


148 


473 


314 


187 


631 


413 


232 


812 


543 


319 


1015 


673 


457 


1491 


983 




5 


51 


63 


44:, 


75 128 


..•66 


102 


216 


i 140 


144 


326 ■ 217 


182 


459 


298 


231 


616 


400 


287 


795 


526 


392 


997 


657 


562 


1469 


963 




10 


NA 


NA 


39 


95 116 


79 


128 


201 


: 131 


182 


308 ; 203:- 


228 


438 


284 


284 


592 


■981 


349 


768 


501" 


470 


966 


628 


664 


1433 


928 




15 


NA 


NA 


NA 


NA NA 


72 


158 


186 


124 


220 


290 t 192 


272 


418 


269 


334 


568 


367 


404 


742 


484 


540 


937 


601 


750 


1399 


894 


20 





35 


96 


60. 


54 200 


lis 


78 


346 


■201 


114 


537 ' 3d6 : 


149 


772 


'428 


190 


1053 


'573 


238 


1379 


750 


326 


1751 


927 


473 


2631 


1346 




2 


37 


74 


50: 


56 148 


99 


78 


248 


165 


113 


375 248 


144 


528 


344 


182 


708 


468 


227 


914 


611 


309 


1146 


754 


443 


1689 


1098 




5 


50 


68 


47 


73 140 


94 


100 


239 


,158 


141 


363 j 239- 


178 


514 


334 


224 


692 


,457 


279 


896 


596 


381 


1126 


734 


547 


1665 


107+ 




10 


NA 


NA 


41 ' 


93 129 


86 


125 


223 


146 


177 


344 ; 224 


222 


491 


316 


277 


606 


437 


339 


866 


570 


457 


1092 


702 


646 


1626 


1037 




15 


NA 


NA 


NA . 


NA NA 


80 


155 


208 


136 


216 


325 210 


264 


469 


301 


325 


640 


419 


393 


838 


549 


526 


1060 


677 


730 


1587 


1005 




20 


NA 


NA 


NA 


NA NA 


NA 


186 


192 


; i26'; 


254 


306 -196: 


309 


448 


285 


374 


616 1 400 


448 


810 


526 


592 


1028 


651 


808 


1550 


973 


30 





34 


99 


63- 


53 211 


127 


76 


372 


219 


110 


584 : 334 


144 


849 


472 


184 


1168 


647 


229 


1542 


852 


312 


1971 


1056 


454 


2996 


1545 




2 


37 


80 


56 


55 164 


111 


76 


281 


183 


109 


429 279- 


139 


610 


392 


175 


823 


533 


219 


1069 


698 


296 


1346 


863 


424 


1999 


1308 




5 


49 


74 


52: 


72 157 


106 


98 


271 


173 


136 


417 271 


171 


595 


382 


215 


806 


521 


269 


1049 


684 


366 


1324 


846 


524 


1971 


1283 




10 


NA 


NA 


NA 


91 144 


98 


122 


255 


■ 168 . 


171 


397 257, 


213 


570 


367 


265 


777 


501 


327 


1017 


662 


440 


1287 


821 


620 


1927 


1243 




15 


NA 


NA 


NA ' 


115 131 


NA 


151 


239 


157 ' 


208 


377 242- 


255 


547 


"349 


312 


750 


481 


379 


985 


638 


507 


1251 


794 


702 


1884 


1205 




20 


NA 


NA 


NA 


NA NA 


NA 


181 


223 


NA 


246 


357 228 


298 


524 


333 


360 


723 


461 


433 


955 


615 


570 


1216 


768 


780 


1841 


1166 




SO 


NA 


NA 


NA 


NA NA 


NA 


NA 


NA 


K'NA- 


NA 


NA NA 


389 


477 


805 


461 


670 \ 426 


541 


895 


574 


704 


1147 


720 


937 


1759 


1101 


50 





33 


99 


66, 


51 213 


133 


73 


394 


230 


105 


629 i 361 


138 


928 


515 


176 


1292 


704 


220 


1724 


948 


295 


2223 


1189 


428 


3432 


1818 




2 


36 


84 


61 


53 181 


121 


73 


318 


205- 


104 


495 312 


133 


712 


443 


168 


971 


613 


209 


1273 


811 


280 


1615 


1007 


401 


2426 


1509 




5 


48 


80 


NA 


70 174 


117 


94 


308 


• 198 


131 


482 i 305 


164 


696 


435 


204 


953 


602 


257 


1252 


795 


347 


1591 


991 


496 


2396 


1490 




10 


NA 


NA 


NA.: 


89 160 


NA 


118 


292 


186 


162 


461 i 292 


203 


671 


420 


253 


923 


583 


313 


1217 


765 


418 


1551 


963 


589 


2347 


1455 




15 


NA 


NA 


v\ 


112 148 


NA 


145 


275 


174 : 


199 


441 •2# 


244 


646 


405" 


299 


894 


562 


363 


1183 


736 


481 


1512 


"934 


668 


2299 


1421' 




20 


NA 


NA 


NA- 


NA NA 


NA 


176 


257 


NA 


236 


420 267 


2S5 


622 


389 


345 


866 


543 


415 


1150 


70S 


544 


1473 


906 


741 


2251 


1387 




30 


NA 


NA 


NA 


NA NA 


,NA 


NA 


NA 


NA 


315 


376 i NA ; 


373 


573 


NA. 


442 


809 1 502 


521 


1086 


649 


674 


1399 


848 


892 


2159 


1318 


100 





NA 


NA 


NA' 


49 214 


tk 


69 


403 


NA 


100 


659 , 395 


131 


991 


555 


166 


1404 


765 


207 


1900 


1033 


273 


2479 


1300 


395 


3912 


2042 




2 


NA 


NA 


N4 


51 192 


NA 


70 


351 


NA 


98 


563 j 37|, 


125 


828 


.508 


158 


1152 


,698 


196 


1532 


933 


259 


1970 


1168 


371 


3021 


1817 




5 


NA 


NA 


NA- 


67 186 


NA 


90 


342 


NA 


125 


551 i 366' 


156 


813 


501 


194 


1134 


688 


240 


1511 


921 


322 


1945 


1153 


460 


2990 


1796 




10 


NA 


NA 


NA 


85 175 


.NA 


113 


324 


NA 


153 


532 , 354 


191 


789 


486 


238 


1104 


672 


293 


1477 


902 


389 


1905 


1133 


547 


2938 


1763 




15 


'NA 


NA 


NA:: 


1S2 162 


NA 


138 


310 


' NA 


188 


511 343, 


230 


764 


473 


281 


1075 


>656 


342 


1443 


884- 


447 


1865 


1110 


618 


2888 


1730 




20 


NA 


NA 


NA- 


NA NA 


NA 


168 


295 


NA 


224 


487 NA. 


270 


739 


458 


325 


1046 


639 


391 


1410 


864 


507 


1825 


1087 


690 


2838 


1696 




30 


NA 


NA 


NA/ 


NA NA 


NA 


231 


264 


NA 


301 


448 , NA, 


355 


685 


NA 


418 


988 


NA 


491 


1343 


824 


631 


1747 


1041 


834 


2739 


1627 




50 


NA 


NA 


NA 
- 


NA NA 


NA 


NA 


NA 


' NA 


NA 


NA ' NA! 


540 


584 


NA 


617 


866 


•NA 


711 


1205 


NA 


895 


1591 


NA 


1138 


2547 


1489 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in. 2 = 645 mm 2 . 



2006 Edition 



54-96 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-96 



Table 13.1(c) Masonry Chimney 





























Number oi 


Appliances: 


Singl 


e 














Appliance Type: 


Category I 




Appliance Vent Connection: 


Type B Double-Wall Connector 


















Type B Double-Wall Connector Diameter 


— D(in.) 


















t Lateral 
L 
(ft) 














To be used with chimney areas within the size 


imits at bottom 
















3 


4 


5 


6 


7 


8 


9 


10 


12 


















Appl 


ance Input 


Rating 


in Thousands of Btu per Hour 
















Heigl 
H 
(ft) 


FAN NAT 


FAN v\l 


FAN 


NAT 

Mai 


FAN iNAtI 


FAN 


> . 


FAN NAT 


FAN 


NAT 
Mas : 


FAN [ 


N.VI 


FAN 


NAT 


Min 


Max 'Max 


Min 


Max jMax 


Min 


Max 


Min 


Max iMax : 


Min 


Max 


Max 


Min 


Max : Max 


Min 


Max 


Min 


Max ] 


Max 


Min 


Max 


Max 


6 


2 


NA 


NA 28 


NA 


NA 52 


NA 


NA 


86 


NA 


NA 130 


NA 


NA 


Hi, 


NA 


NA 247 


NA 


NA 


320 


NA 


NA !' 


101 


NA 


NA 


581! 




5 


NA 


NA ! 25 


NA 


NA ! 49 


NA 


NA 


- -82 


NA 


NA 1 117 


NA 


NA 


165: 


NA 


NA 231 


NA 


NA 


298 ; 


NA 


NA 


'376 


NA 


NA : 


561 


8 


2 


NA 


NA 29 


NA 


NA 


NA 


NA 


93 


NA 


NA ' 145 


NA 


NA 




NA 


NA "266 


84 


590 


350 


100 


728 : 


146 


139 


1024 


65.1 




5 


NA 


NA I 26 


NA 


NA j 52 


NA 


NA 


. 88 


NA 


NA i 134 


NA 


NA 


183' 


NA 


NA 1 : 247 


NA 


NA 


328: 


149 


711 : 


423 


201 


1007 


640 




8 


NA 


NA 24 


NA 


NA 48 


NA 


NA 


^ 


NA 


NA 127 


NA 


NA 


175 


NA 


NA 239 


NA 


NA 




173 


695 j 


410 


231 


990 


. 623 


10 


2 


NA 


1 
NA ;;v SI 


NA 


NA \ 61 


NA 


NA 


103 


NA 


NA ! 162:' 


NA 


NA 


221 


68 


519 U 298 


82 


655 


388! 


98 


810 ■ 


491 


136 


1144 


724 




5 


NA 


NA 28 


NA 


NA 


NA 


NA 


% 


NA 


NA 1 18 


NA 


NA 




NA 


NA 277 


124 


638 • 


368i 


146 


791 J 


.„.,. 


196 


1124 ; 


712 




10 


NA 


NA , 25' 


NA 


NA ' 50 
[ ;: : 


NA 


NA 


87 


NA 


NA ' 139 


NA 


NA 


191 


NA 


NA 263 


155 


610 ' 


347- 


182 


762 ' 


44! 


240 


1093 : 


668, 


15 


2 


NA 


NA 35 


NA 


NA 67 


NA 


NA 


114 


NA 


NA ! 179 


53 


475 


■m 


64 


613 336 


77 


779 


44! 


92 


968 J 


562 


127 


1376 


841 




5 


NA 


NA ! 35 


NA 


NA | 02 


NA 


NA 


11)7 


NA 


NA 164 


NA 


NA 


231 


99 


594 '313 


118 


759 


416 


139 


946 | 


533 


186 


1352 


828 




10 


NA 


NA | 28 


NA 


NA : 55 


NA 


NA 


97 


NA 


NA 153 


NA 


NA 


216 


126 


565 296 


148 


727 


394 


173 


912 ! 


"•67 


229 


1315 ! 


777 




15 


NA 


NA NA 


NA 


NA 18 


NA 


NA 


89 


NA 


NA 


NA 


NA 


2(11 


NA 


NA 281 


171 


698 


3 75 


198 


880 ! 


485 


259 


1280 : 


742 


20 


2 


NA 


NA ■ 38 


NA 


NA ' '74 


NA 


NA 


124 


NA 


NA 201 


51 


522 




61 


678 375 


73 


867 


491 


87 


1083 : 


627 


121 


1548 


953 




5 


NA 


NA 3fi 


NA 


NA : 


NA 


NA 


116 


NA 


NA 181 


80 


503 


'■■>: 


95 


658 350 


113 


845 


163 


133 


1059 • 


597 


179 


1523 


933 




10 


NA 


NA [ NA' 


NA 


NA ■ 60 


NA 


NA 


107 


NA 


NA I 172' 


NA 


NA 


237 


122 


627 : 332 


143 


811 


440 


167 


1022 


566 


221 


1482 


879 




15 


NA 


NA NA 


NA 


NA NA 


NA 


NA 


97 


NA 


NA 15') 


NA 


NA 


220 


NA 


NA 314 


165 


780 


41 S 


191 


987 i 


541 


251 


1443 


. B40 




20 


NA 


NA NA 


NA 


N-\ NA 


NA 


NA 


S3 


NA 


NA [148' 


NA 


NA 


206 


NA 


NA 296 


186 


750 


397. 


214 


955 


513 


277 


1406 


807 


30 


2 


NA 


NA ' : 


NA 


NA - 


NA 


NA 


13, 


NA 


NA 


47 


581 




57 


762 ' 421 


68 


985 


558 


81 


1240 j 


'717 


111 


1793 


11 12 




5 


NA 


NA NA 


NA 


NA ! 76 


NA 


NA 


138 


NA 


NA i 198' 


75 


561 




90 


741 393 


106 


962 


526' 


125 


1216 ; 


'683 


169 


1766 


1094 




10 


NA 


NA NA 


NA 


NA 1 67 


NA 


NA 


1J5 


NA 


NA 184 


NA 


NA 


263 


115 


709 "• 373 


135 


927 


500 


158 


1176 j 


648 


210 


1721 


1025 




15 


NA 


NA ■ . 


NA 


NA N-A 


NA 


NA 


10, 


NA 


NA ■ 171 


NA 


NA 


'24S ; 


NA 


NA 353 


156 


893 


'; 47b; 


181 


1139 1 


621 


239 


1679 


' 981 




20 


NA 


NA NA 


NA 


NA i NA 


NA 


NA 


91 


NA 


NA 159 


NA 


NA 


227 


NA 


NA H 332 


176 


860 


450: 


203 


1103 I 


592 


264 


1638 


940 




30 


NA 


NA NA 


NA 


NA NA 


NA 


NA 


NA 


NA 


NA NA 


NA 


NA 


188 


NA 


NA ; 288 


NA 


NA 


416 


249 


1035 : 


:..f>S5 


318 


1560 


377 


50 


2 


NA 


NA i-NA 


NA 


NA j 92 


NA 


NA 


161 


NA 


NA i 251 


NA 


NA 


351 


51 


840 1 1 477 


61 


1106 


633' 


72 


1413 : 


812 


99 


2080 


1243 




5 


NA 


NA NA 


NA 


NA \- 


NA 


NA 


151 


NA 


NA 230' 


NA 


NA 


. 323. 


83 


819 : 445 


98 


1083 


59,' 


116 


1387 t 


774 


155 


2052 


,1225 




10 


NA 


NA NA 


NA 


NA . N'A 


NA 


NA 


it r . 


NA 


NA : 215 ' 


NA 


NA 


.-.Mi 


NA 


NA 424 


126 


1047 


567 


147 


1347 1 


733 


195 


2006 


1147: 




15 


NA 


NA '.NA 


NA 


NA i NA 


NA 


NA 


M27 


NA 


NA i 199" 


NA 


NA 


282 


NA 


NA i 400 


146 


1010 


539. 


170 


1307 


702 


222 


1961 


1099 




20 


NA 


NA NA 


NA 


NA , NA 


NA 


NA 


. NA 


NA 


N\ 185 


NA 


NA 




NA 


NA " 


165 


977 


all 


190 


1269 s 


669 


246 


1916 


1050 




30 


NA 


NA NA 


NA 


NA ; NA 


NA 


NA 


,=: NA 


NA 


NA 1 NaI 


NA 


NA 


NA 


NA 


NA j" 327 


NA 


NA 


468 


233 


1196 


623 


295 


1832 


984 


Minimum 




12 




19 




28 






3, 




50 


■:.'.?' 




63 . - ■ 




78 






95 ' 


-,,;:,„ 




132 






internal 








j \:£: 




















fit 






















area of 




!■;; 




' 










































chimney 
(■n. 2 ) 














IpT" 




\~% 






: 




W^?' ' 






: '3 




1 


W' 








Maximum 




49 




it -A 
88 




137 






198 




269 


jJ.'t'S 




352 ' ' 




445 






550 j 






792 






internal 








i'.'r-f 
















::"' 




:':..:' 






















area of 
























, '; ;. 




[■:.; 






















chimney 
On- 2 ) 




\-:"t 




; 









































For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in. 2 = 645 mm- 1 



2006 Edition 



ANSI Z223. 1-97 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-97 



Table 13.1 (d) Masonry Chimney 





t Lateral 
L 
(ft) 




















Number of Appliances: 


Single 
















Appli 


ance Type: 


Category I 












Appliancf 


Vent Connection: 


Single-Wall 


Metal Connector 












Single-Wall Metal Connector Diameter — D (in.) 
To be used with chimney areas within the size limits at bottom 




3 


4 


5 


6 


7 


8 


9 


10 


12 




Appliance Input Rating in Thousands of Btu per Hour 


Heigh 
H 

(ft) 


FAN 


NAT 

-•< ... 


FAN 


NAT-.' 

Max; 


FAN 


NAT 
Max 


FAN 


NAT. 


FAN 


NAT 


FAN 


NAT 


FAN 


NAT 


FAN 


NAT 


FAN 


NAT 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max 


M it 


Min 


Max 


Max 


Min 


Max 


Max 


Min 


Max 


Max 


Min 


Max 


Max 


Min 


Max 


Max 


6 


2 


NA 


NA 


.28 


NA 


NA 


52 


NA 


NA 


86 


NA 


NA 


1 -.ii 


NA 


NA 


180 


NA 


NA 


247 


NA 


NA 


319 


NA 


NA 


400 


NA 


NA 


580 




5 


NA 


NA 


' 25: 


NA 


NA 


■IS 


NA 


NA 


' w 


NA 


NA 


116 


NA 


NA 


164! 


NA 


NA 


230 


NA 


NA 


297 


NA 


NA 


375 


NA 


NA 


560 


8 


2 


NA 


NA 


29; 


NA 


NA 




NA 


NA 


93: 


NA 


NA 


145- 


NA 


NA 


197 


NA 


NA 


265 


NA 


NA 


349 


382 


725 


445 


549 


1021 


650 




5 


NA 


NA 




NA 


NA 


11 


NA 


NA 


87 


NA 


NA 


133; 


NA 


NA 


isr 


NA 


NA 


246 


NA 


NA 


327: 


NA 


NA 


422 


673 


1003 


638 




8 


NA 


NA 


23 : , 


NA 


NA 


47' 


NA 


NA 


82' 


NA 


NA 


126',; 


NA 


NA 


174 


NA 


NA 


237 


NA 


NA 


317 


NA 


NA 


408 


747 


985 


621 


10 


2 


NA 


NA 




NA 


NA 


01 


NA 


NA 


1(11' 


NA 


NA 


161 


NA 


NA 


220 


216 


518 


297 


271 


654 


38,7. 


373 


808 


490 


536 


1142 


722 




5 


NA 


NA 


.- 


NA 


NA 


36 


NA 


NA 


95 


NA 


NA 


147 


NA 


NA 


203 


NA 


NA 


276 


334 


635 


364 


459 


789 


465 


657 


1121 


710 




10 


NA 


NA 


24 


NA 


NA 


49; 


NA 


NA 


86? 


NA 


NA 


137 


NA 


NA 


189 


NA 


NA 


261 


NA 


NA 


345 


547 


758 


441 


771 


1088 


665 


15 


2 


NA 


NA 


: 35 


NA 


NA 


67 


NA 


NA 


in 


NA 


NA 


1 78 


166 


473 


24'J 


211 


611 


'335 


264 


776 


440 


362 


965 


560 


520 


1373 


840 




5 


NA 


NA 


32 


NA 


NA 


61 


NA 


NA 


106 


NA 


NA 


163 


NA 


NA 


230 


261 


591 


312 


325 


755 


414 


444 


942 


531 


637 


1348 


825 




10 


NA 


NA 


■27- 


NA 


NA 


5-1 


NA 


NA 


96 


NA 


NA 


•151: 


NA 


NA 


214 


NA 


NA 


294 


392 


722 


392 


531 


907 


504 


749 


1309 


774 




15 


NA 


NA 


:, , 


NA 


NA 


4>j 


NA 


NA 


87 


NA 


NA 


138 


NA 


NA 


l''8 


NA 


NA 


278 


452 


692 


372 


606 


873 


481 


841 


1272 


738 


20 


2 


NA 


NA 


•if 


NA 


NA 


"■ 


NA 


NA 


123 


NA 


NA 


>0<J 


163 


520 


273 


206 


675 


374 


258 


864 


490 


252 


1079 


625 


508 


1544 


950 




5 


NA 


NA 




NA 


NA 


67 


NA 


NA 


: 116 


NA 


NA 


183. 


NA 


NA 


252 


255 


655 


348 


317 


842 


461 


433 


1055 


594 


623 


1518 


930 




10 


NA 


NA 


NA 


NA 


NA 


59" 


NA 


NA 


105 


NA 


NA 


170 


NA 


NA 


235 


312 


622 


330 


382 


806 


437 


517 


1016 


562 


733 


1475 


875 




15 


NA 


NA 


NA 


NA 


NA 


NA; 


NA 


NA 


95 


NA 


NA 


156 


NA 


NA 


217. 


NA 


NA 


311 


442 


773 


414 


591 


979 


539 


823 


1434 


835 




20 


NA 


NA 


"NA; 


NA 


NA 


w 


NA 


NA 


80 


NA 


NA 


144, 


NA 


NA 


202 


NA 


NA 


292 


NA 


NA 


392 


663 


944 


510 


911 


1394 


800 


30 


2 


NA 


NA 


41 


NA 


NA 


81 


NA 


NA 


136 


NA 


NA 


215 


158 


578 


302 


200 


759 


420 


249 


982 


556 


340 


1237 


715 


489 


1789 


1110 




5 


NA 


NA 


V\ 


NA 


NA 


75 


NA 


NA 




NA 


NA 


PI'. 


NA 


NA 


279 


245 


737 


39) : 


306 


958 


524 


417 


1210 


,680 


600 


1760 


1090 




10 


NA 


NA 


NA 


NA 


NA 


66 


NA 


NA 


113 


NA 


NA 


182 


NA 


NA 


260 


300 


703 


370 


370 


920 


496 


500 


1168 


644 


708 


1713 


1020 




15 


NA 


NA 


NA, 


NA 


NA 


NA:; 


NA 


NA 


105 


NA 


NA 


168 


NA 


NA 


240 


NA 


NA 


349 


428 


884 


471 


572 


1128 


615 


798 


1668 


975 




20 


NA 


NA 


■..■ 


NA 


NA 


N'. 


NA 


NA 


H* 


NA 


NA 


'.!&&.■ 


NA 


NA 


223- 


NA 


NA 


327 


NA 


NA 


4*5 


643 


1089 


•585 


883 


1624 


932 




30 


NA 


NA 


KA- 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


182 


NA 


NA 


281 


NA 


NA 


408 


NA 


NA 


544 


1055 


1539 


865 


50 


2 


NA 


NA 


MA 


NA 


NA 


91 


NA 


NA 


160, 


NA 


NA 


250 


NA 


NA 


350 


191 


837 


475 


238 


1103 


631 


323 


1408 


810 


463 


2076 


1240 




5 


NA 


NA 


\\ 


NA 


NA 


NX 


NA 


NA 


in 


NA 


NA 


223 


NA 


NA 


321 


NA 


NA 


'442 


293 


1078 


593 


398 


1381 


•770 


571 


2044 


1220 




10 


NA 


NA 


NA. 


NA 


NA 


NA* 


NA 


NA 


136 


NA 


NA 


212- 


NA 


NA 


301. 


NA 


NA 


420 


355 


1038 


562 


447 


1337 


728 


674 


1994 


1140 




15 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


i:l 


NA 


NA 


l!»r. 


NA 


NA 


y-s 


NA 


NA 


395 


NA 


NA 


533 


546 


1294 


695 


761 


1945 


1090 




20 


NA 


NA 


NA 


NA 


NA 


NA- 


NA 


NA 


V\ 


NA 


NA 


1K(1 


NA 


NA 


258 


NA 


NA 


370 


NA 


NA 


504 


616 


1251 


660 


844 


1898 


1040 




30 


NA 


NA 


NA; 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


318 


NA 


NA 


458 


NA 


NA 


610 


1009 


1805 


970 


Minimum 
internal area 
of chimney 

(in. 2 ) 




12 


\ J; 
: 


19 : ' ! *!i 




28 






38 




50 


63 




78 


95 ! 


132 ; 


Maximum 
internal area 
of chimney 
(in. 2 ) 




49 




88 




137 






198 




269 


352 ' 




445 


'# 


550 


792 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in. 2 = 645 mm 2 . 



2006 Edition 



54-98 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-98 



Table 1 3. 1 (e) Single-Wall Metal Pipe or Type B Asbestos Cement Vent 











Number of Appliances: 


Single 




Appliance Type: 


Draft Hood-Equipped 




Appliance Vent Connection: 


Connected Directly to Pipe or Vent 










Diameter - D (in.) 






Lateral 
L 






To be used with chimney areas within the size limits at bottom 






3 


4 


5 


6 


7 


8 


10 


12 


Height 
H 


Appliance Input Rating in Thousands of Btu per Hour 










(ft) 


(ft) 






Maximum Appliance Input Rating in Thousands of Btu per Hour 




6 





39 


70 


116 


170 


232 


312 


500 


750 




2 


31 


55 


94 


141 


194 


260 


415 


620 




5 


28 


51 


88 


128 


177 


242 


390 


600 


8 





42 


76 


126 


185 


252 


340 


542 


815 




2 


32 


61 


102 


154 


210 


284 


451 


680 




5 


29 


56 


95 


141 


194 


264 


430 


648 




10 


24 


49 


86 


131 


180 


250 


406 


625 


10 





45 


84 


138 


202 


279 


372 


606 


912 




2 


35 


67 


111 


168 


233 


311 


505 


760 




5 


32 


61 


104 


153 


215 


289 


480 


724 




10 


27 


54 


94 


143 


200 


274 


455 


700 




15 


NA 


46 


84 


130 


186 


258 


432 


666 


15 





49 


91 


151 


223 


312 


420 


684 


1040 




2 


39 


72 


122 


186 


260 


350 


570 


865 




5 


35 


67 


110 


170 


240 


325 


540 


825 




10 


30 


58 


103 


158 


223 


308 


514 


795 




15 


NA 


50 


93 


144 


207 


291 


488 


760 




20 


NA 


NA 


82 


132 


195 


273 


466 


726 


20 





53 


101 


163 


252 


342 


470 


770 


1190 




2 


42 


80 


136 


210 


286 


392 


641 


990 




5 


38 


74 


123 


192 


264 


364 


610 


945 




10 


32 


65 


115 


178 


246 


345 


571 


910 




15 


NA 


55 


104 


163 


228 


326 


550 


870 




20 


NA 


NA 


91 


149 


214 


306 


525 


832 


30 





56 


108 


183 


276 


384 


529 


878 


1370 




2 


44 


84 


148 


230 


320 


441 


730 


1140 




5 


NA 


78 


137 


210 


296 


410 


694 


1080 




10 


NA 


68 


125 


196 


274 


388 


656 


1050 




15 


NA 


NA 


113 


177 


258 


366 


625 


1000 




20 


NA 


NA 


99 


163 


240 


344 


596 


960 




30 


NA 


NA 


NA 


NA 


192 


295 


540 


890 


50 





NA 


120 


210 


310 


443 


590 


980 


1550 




2 


NA 


95 


171 


260 


370 


492 


820 


1290 




5 


NA 


NA 


159 


234 


342 


474 


780 


1230 




10 


NA 


NA 


146 


221 


318 


456 


730 


1190 




15 


NA 


NA 


NA 


200 


292 


407 


705 


1130 




20 


NA 


NA 


NA 


185 


276 


384 


670 


1080 




30 


NA 


NA 


NA 


NA 


222 


330 


605 


1010 



For SI units, 1 in. = 25.4 mm, 1 ft = 0.305 m, 1000 Btu/hr = 0.293 kW, 1 in. 2 = 645 mm 2 



2006 Edition 



ANSI Z223.1-99 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-99 



Table 13.1 (f) Exterior Masonry Chimney 



Number of Appliances: 



Appliance Type: 



Appliance Vent Connection: 



Single 



NAT 



Type B Double-Wall Connector 





SPECIAL L'SE: Minimum 


Allowable Input Rating 


i>! Sjvrf-t tearing AnpUiwa ">it Thousands <>f B*n i<er Hour 




Vent Height 








Internal Area of Chimney (ir 


• 2 ) 








H 

(ft) 


12 


19 


28 




38 


50 




63 


78 


113 


6 








Local 99% winter design temperature: 37°F o 



" greater 









8 






























10 






























15 


NA 



























20 


NA 


NA 


123 




190 


249 




184 








30 


NA 


NA 


NA 




NA 


NA 




393 


334 





50 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


579 


6 








68 


-ocal 99% 


winter design temperature: 
116 156 


27°F 


uo 36°F 

180 


212 


266 


8 








82 




127 


167 




187 


214 


263 


10 





51 


97 




141 


183 




201 


225 


265 


15 


NA 


NA 


NA 




NA 


233 




253 


274 


305 


20 


NA 


NA 


NA 




NA 


NA 




307 


330 


362 


30 


NA 


NA 


NA 




NA 


NA 




419 


445 


485 


50 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


763 


6 


NA 


NA 


Local 99% 

NA 


winter design temperature: 

NA NA 


17°Fto26°F 

215 


259 


349 


8 


NA 


NA 


NA 




NA 


197 




226 


264 


352 


10 


NA 


NA 


NA 




NA 


214 




245 


278 


358 


15 


NA 


NA 


NA 




NA 


NA 




296 


331 


398 


20 


NA 


NA 


NA 




NA 


NA 




352 


387 


457 


30 


NA 


NA 


NA 




NA 


NA 




NA 


507 


581 


50 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


NA 


6 


NA 


NA 


NA 


Local 99% 


winter design temperature 

NA NA 


5°F to 16°F 

NA 


NA 


416 


8 


NA 


NA 


NA 




NA 


NA 




NA 


312 


423 


10 


NA 


NA 


NA 




NA 


NA 




289 


331 


430 


15 


NA 


NA 


NA 




NA 


NA 




NA 


393 


485 


20 


NA 


NA 


NA 




NA 


NA 




NA 


450 


547 


30 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


682 


50 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


972 


6 


NA 


NA 


Local 99% 

NA 


winter design temperature: 

NA NA 


-10°F to 4°F 

NA 


NA 


484 


8 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


494 


10 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


513 


15 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


586 


20 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


650 


30 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


805 


50 


NA 


NA 


NA 




NA 


NA 




NA 


NA 


1003 








Local 99% winter design temperature: -11°F 
Not recommended for any vent configura 


or lower 
ions 







For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW, °C = (°F - 32)/l. 
Note: See Figure G.2.4 for a map showing local 99 percent winter design temperatures in the United States. 



2006 Edition 



54-100 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-100 



13.2 Additional Requirements to Multiple-Appliance Vent. 

13.2.1 Obstructions and Vent Dampers. Venting Table 13.2 (a) 
through Table 13.2(i) shall not be used where obstructions (see 
Section 12.16) are installed in the venting system. The installa- 
tion of vents serving listed appliances with vent dampers shall 
be in accordance with the appliance manufacturer's instruc- 
tions, or in accordance with the following: 

(1) The maximum capacity of the vent connector shall be 
determined using the NAT Max column. 

(2) The maximum capacity of the vertical vent or chimney shall 
be determined using the FAN+NAT column when the sec- 
ond appliance is a fan-assisted appliance, or the NAT+NAT 
column when the second appliance is equipped with a draft 
hood. 

(3) The minimum capacity shall be determined as if the ap- 
pliance were a fan-assisted appliance, as follows: 

(a) The minimum capacity of the vent connector shall be 
determined using the FAN Min column. 

(b) The FAN+FAN column shall be used when the second 
appliance is a fan-assisted appliance, and the FAN+NAT 
column shall be used when the second appliance is 
equipped with a draft hood, to determine whether the 
vertical vent or chimney configuration is not permitted 
(NA) . Where the vent configuration is NA, the vent con- 
figuration shall not be permitted and an alternative 
venting configuration shall be utilized. 

13.2.2 Vent Connector Maximum Length. The maximum vent 
connector horizontal length shall be 18 in. /in. (18 mm/mm) 
of connector diameter as shown in Table 13.2.2. 

Table 1 3 . 2 . 2 Vent Connector Maximum Length 





Connector 




Connector 


Connector 


Horizontal 


Connector 


Horizontal 


Diameter Max. 


Length 


Diameter Max. 


Length 


(in.) 


(ft) 


(in.) 


(ft) 


3 


4!4> 


12 


18 


4 


6 


14 


21 


5 


71/2 


16 


24 


6 


9 


18 


27 


7 


IOV2 


20 


30 


8 


12 


22 


33 


9 


13V2 


24 


36 


10 


15 







For SI units, 1 in. = 25.4 ram; 1 ft = 0.305 m. 

13.2.3 Vent Connector Exceeding Maximum Length. The 

vent connector shall be routed to the vent utilizing the short- 
est possible route. Connectors with longer horizontal lengths 
than those listed in Table 13.2.2 are permitted under the fol- 
lowing conditions: 

( 1 ) The maximum capacity (FAN Max or NAT Max) of the vent 
connector shall be reduced 10 percent for each additional 
multiple of the length listed in Table 13.2.2. For example, 
the maximum length listed for a 4 in. (100 mm) connectoris 
6 ft (1.8 m). With a connector length greater than 6 ft 
(1.8 m) but not exceeding 12 ft (3.7 m), the maximum ca- 
pacity must be reduced by 10 percent (0.90 x maximum vent 
connector capacity) . With a connector length greater than 
12 ft (3.7 m) but not exceeding 18 ft (5.5 m), the maximum 
capacity must be reduced by 20 percent (0.80 x maximum 
vent capacity). 



(2) For a connector serving a fan-assisted appliance, the mini- 
mum capacity (FAN Min) of the connector shall be deter- 
mined by referring to the corresponding single appliance 
table. For Type B double-wall connectors, Table 13.1(a) 
shall be used. For single-wall connectors, Table 13.1(b) 
shall be used. The height (H) and lateral (L) shall be mea- 
sured according to the procedures for a single appliance 
vent, as if the other appliances were not present. 

13.2.4 Vent Connector Manifolds. Where the vent connectors 
are combined prior to entering the vertical portion of the com- 
mon vent to form a common vent manifold, the size of the com- 
mon vent manifold and the common vent shall be determined by 
applying a 10 percent reduction (0.90 x maximum common vent 
capacity) to the Common Vent Capacity part of the common vent 
tables. The length of the common vent manifold (LM) shall not 
exceed 18 in. /in. (18 mm/mm) of common vent diameter (D). 

13.2.5 Vent Offsets. Where the common vertical vent is offset, 
the maximum capacity of the common vent shall be reduced 
in accordance with 13.2.6 and the horizontal length of the 
common vent offset shall not exceed 18 in. /in. (18 mm/mm) 
of common vent diameter (D). 

13.2.6 Elbows in Vents. For each elbow up to and including 
45 degrees in the common vent, the maximum common vent 
capacity listed in the venting tables shall be reduced by 5 per- 
cent. For each elbow greater than 45 degrees up to and includ- 
ing 90 degrees, the maximum common vent capacity listed in 
the venting tables shall be reduced by 10 percent. 

13.2.7 Elbows in Connectors. The vent connector capacities 
listed in the common vent sizing tables include allowance for two 
90 degree elbows. For each additional elbow up to and including 
45 degrees, the maximum vent connector capacity listed in the 
venting tables shall be reduced by 5 percent. For each elbow 
greater than 45 degrees up to and including 90 degrees, the 
maximum vent connector capacity listed in the venting tables 
shall be reduced by 10 percent. 

13.2.8 Common Vent Minimum Size. The cross-sectional area 
of the common vent shall be equal to or greater than the cross- 
sectional area of the largest connector. 

13.2.9 Tee and Wye Fittings. Tee and wye fittings connected to 
a common vent shall be considered as part of the common 
vent and constructed of materials consistent with that of the 
common vent. 

13.2.10 Tee and V/ye Sizing. At the point where tee or wye fit- 
tings connect to a common vent, the opening size of the fitting 
shall be equal to the size of the common vent. Such fittings 
shall not be prohibited from having reduced size openings at 
the point of connection of appliance vent connectors. 

13.2.11 High Altitude Installations. Sea level input ratings shall 
be used when determining maximum capacity for high-altitude 
installation. Actual input (derated for altitude) shall be used for 
determining minimum capacity for high-altitude installation. 

13.2.12 Connector Rise. The connector rise (R) for each appli- 
ance connector shall be measured from the draft hood outlet or 
flue collar to the centerline where the vent gas streams come 
together. 

13.2.13 Vent Height. For multiple appliances all located on 
one floor, available total height (H) shall be measured from 
the highest draft hood outlet or flue collar up to the level of 
the outlet of the common vent. 



2006 Edition 



ANSIZ223.1-101 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-101 



13.2.14 Multistory Vent Height. For multistory installations, 
available total height (H) for each segment of the system shall 
be the vertical distance between the highest draft hood outlet 
or flue collar entering that segment and the centerline of the 
next higher interconnection tee. [See Figure G.l(m).] 

13.2.15 Multistory Lowest Vent and Vent Connector Sizing. The 

size of the lowest connector and of the vertical vent leading to the 
lowest interconnection of a multistory system shall be in accor- 
dance with Table 13.1(a) or Table 13.1(b) for available total 
height (H)\xp to the lowest interconnection. [See Figure G.l(n).] 

13.2.16 Multistory B Vents Required. Where used in multi- 
story systems, vertical common vents shall be Type B double- 
wall and shall be installed with a listed vent cap. 

13.2.17 Multistory Vent Offsets and Capacity. Offsets in mul- 
tistory common vent systems shall be limited to a single offset 
in each system, and systems with an offset shall comply with all 
of the following: 

( 1 ) The offset angle shall not exceed 45 degrees from vertical. 

(2) The horizontal length of the offset shall not exceed 
18in./in. (18 mm/mm) of common vent diameter of the 
segment in which the offset is located. 

(3) For the segment of the common vertical vent containing the 
offset, the common vent capacity listed in the common vent- 
ing tables shall be reduced by 20 percent (0.80 x maximum 
common vent capacity) . 

(4) A multistory common vent shall not be reduced in size 
above the offset. 

13.2.18 Vertical Vent Size Limitation. Where two or more ap- 
pliances are connected to a vertical vent or chimney, the flow 
area of the largest section of vertical vent or chimney shall not 
exceed seven times the smallest listed appliance categorized 
vent areas, flue collar area, or draft hood outlet area unless 
designed in accordance with approved engineering methods. 

13.2.19 Two Stage/Modulating Appliances. For appliances 
with more than one input rate, the minimum vent connector 
capacity (FAN Min) determined from the tables shall be less than 
the lowest appliance input rating, and the maximum vent con- 
nector capacity (FAN Max or NAT Max) determined from the 
tables shall be greater than the highest appliance input rating. 

13.2.20* Corrugated Chimney Liners. Listed corrugated metal- 
lic chimney liner systems in masonry chimneys shall be sized by 
using Table 13.2(a) or Table 13.2(b) for Type B vents, with the 
maximum capacity reduced by 20 percent (0.80 x maximum ca- 
pacity) and the minimum capacity as shown in Table 13.2(a) or 
Table 13.2(b). Corrugated metallic liner systems installed with 
bends or offsets shall have their maximum capacity further re- 
duced in accordance with 13.2.5 and 13.2.6. The 20 percent re- 
duction for corrugated metallic chimney liner systems includes 
an allowance for one long radius 90 degree turn at the bottom of 
the liner. 

13.2.21 Connections to Chimney Liners. Where double-wall 
connectors are required, tee and wye fittings used to connect 
to the common vent chimney liner shall be listed double-wall 
fittings. Connections between chimney liners and listed 
double-wall fittings shall be made with listed adapter fittings 
designed for such purpose. 

13.2.22 Chimneys and Vent Locations. Table 13.2(a) and 
Table 13.2(b) shall be used only for chimneys and vents not 
exposed to the outdoors below the roof line. A Type B vent 
passing through an unventilated enclosure or chase insu- 
lated to a value of not less than R8 shall not be considered 



to be exposed to the outdoors. Table 13.2(f), Table 13.2(g), 
Table 13.2(h), and Table 13.2(i) shall be used for clay-tile- 
lined exterior masonry chimneys, provided all the following 
conditions are met: 

(1) The vent connector is Type B double-wall. 

(2) At least one appliance is draft hood-equipped. 

(3) The combined appliance input rating is less than the 
maximum capacity given by Table 1 3.2 (f) (for NAT+NAT) 
or Table 13.2(h) (for FAN+NAT) . 

(4) The input rating of each space-heating appliance is 
greater than the minimum input rating given by Table 
13.2(g) (for NAT+NAT) or Table 13.2(i) (for FAN+NAT) . 

(5) The vent connector sizing is in accordance with Table 13.2(c). 

(6) Where the conditions of 13.2.22(1) through (5) cannot be 
met, an alternative venting design shall be used, such as a 
listed chimney lining system. 

Exception: Vents serving listed appliances installed in accordance 
with the appliance manufacturer's installation instructions. 

13.2.23 Draft Hood Conversion Accessories. Draft hood con- 
version accessories for use with masonry chimney venting 
listed Category I fan-assisted appliances shall be listed and in- 
stalled in accordance with the listed accessory manufacturer's 
installation instructions. 

13.2.24 Vent Connector Sizing. Vent connectors shall not be in- 
creased more than two sizes greater than the listed appliance 
categorized vent diameter, flue collar diameter, or draft hood 
oudet diameter. Vent connectors for draft hood-equipped appli- 
ances shall not be smaller than the draft hood oudet diameter. 
Where a vent connector size (s) determined from the tables for a 
fan-assisted appliance(s) is smaller than the flue collar diameter, 
the use of the smaller size(s) shall be permitted, provided that 
the installation complies with all of the following conditions: 

(1) Vent connectors for fan-assisted appliance flue collars 12 in. 
(300 mm) in diameter or smaller are not reduced by more 
than one table size [e.g., 12 in. to 10 in. (300 mm to 250 mm) 
is a one-size reduction], and those larger than 12 in. 
(300 mm) in diameter are not reduced more than two table 
sizes [e.g., 24 in. to 20 in. (610 mm to 510 mm) is a two-size 
reduction] . 

(2) The fan-assisted appliance (s) is common vented with a 
draft hood-equipped appliance (s) . 

(3) The vent connector has a smooth interior wall. 

13.2.25 Multiple Vent and Connector Sizes. All combinations 
of pipe sizes, single-wall, and double-wall metal pipe shall be al- 
lowed within any connector run (s) or within the common vent, 
provided ALL of the appropriate tables permit ALL of the de- 
sired sizes and types of pipe, as if they were used for the entire 
length of the subject connector or vent. Where single-wall and 
Type B double-wall metal pipes are used for vent connectors 
within the same venting system, the common vent shall be sized 
using Table 13.2(b) or Table 13.2(d) as appropriate. 

13.2.26 Multiple Vent and Connector Sizes Permitted. Where 
a Chapter 13 table permits more than one diameter of pipe to 
be used for a connector or vent, all the permitted sizes shall be 
permitted to be used. 

13.2.27 Interpolation. Interpolation shall be permitted in cal- 
culating capacities for vent dimensions that fall between table 

entries. (See Example 3, Annex G.) 

13.2.28 Extrapolation. Extrapolation beyond the table entries 
shall not be permitted. 

13.2.29 Sizing Vents Not Covered by Tables. For vent heights 
lower than 6 ft (1.8 m) and higher than shown in the tables, 
engineering methods shall be used to calculate vent capacities. 



2006 Edition 



54-102 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-102 



Table 13.2(a) Type B Double-Wall Vent 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Type B Double-Wall Connector 



Vent Connector Capacity 



















Type B Double-Wall Vent and Connector Diameter — 


D(in 


■) 










3 


4 


5 


6 


7 


8 


9 


10 




Appliance Input Rating Limits in Thousands of Btu per Hour 


Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


ma r 

Max 


FAN NA 1 


FAN \\l 


FAN \A 1 


FAN \A 1 


FAN 


NAT 


FAN N . 


FAN 


NAT 


Min 


Wax 


Min 


Max Max 


Min 


Max M:i\ 


Min 


Max Max 


Min 


M.i\ Mux 


Min 


Max 


Max 


Min 


Max Max Vlin Max 


Max 


6 


1 


22 


37 


26 


35 


66 


46 


106 


58 


164 101 


77 


225 1!2 


92 


296 


185 


109 


376 


<>.< 7 


128 466 


_"•■• 




2 


23 


41 




37 


75 


48 


121 


60 


183 


79 


253 .168 


95 


333 


220 


112 


424 


282 


131 526 


545 




3 


24 


44 


35 


38 


81 62 


49 


133 


62 


199 139 


82 


275 189 


97 


363 




114 


463 317 


134 575 


386 


8 


1 


22 


40 


27 


35 


72 48 


49 


1 1 1 76 


64 


176 109 


84 


243 148 


100 


320 


194 


118 


408 243 


138 507 


303 




2 


23 


44 


32 


36 


80 !!:#< 


51 


1! 


66 


11 


86 


269 175 


103 


356 


23m 


121 


454 294 


141 564 


358 




3 


24 


47 


;i(j 


37 


" 


53 


139 l'H 


67 


210 I'm 


88 


290 198 


105 


384 


258 


123 


492 330 


143 612 


402 


10 


1 


22 


43 


2,s 


34 


78 50 


49 


123 


65 


189 J 13 


89 


257 .154 


106 


341 


200 


125 


436 257 


146 542 


31 1 




2 


23 


47 


33 


36 


86 59 


51 


136 


67 


206 


91 


2 


109 


374 


238 


128 


479 305 


149 596 


372 




3 


24 


50 


.37 


37 


92 67 


52 


146 101 


69 


220 150 


94 


303 205. 


111 


402 




131 


515 342 


152 642 


41V 


15 


1 


21 


50 


30 


33 


89 53 


47 


142 


64 


220 


88 


2 1 - 'tf 


110 


389 


214 


134 


493 ,.273. 


162 609 






2 


22 


53 


35 


35 


96 63 


49 


153 


66 


235 


91 


3 


112 


419 


253 


137 


532 .323 


165 658 


394 




3 


24 


55 


40 


36 


102 71 


51 


163 


68 


248 160 


93 


339 218 


115 


445 


286 


140 


n65 305 


167 700 


444 


20 


1 


21 


54 


31 


33 


99 56 


46 


157 


62 


246 125 


86 


334 17! 


107 


436 


221 


131 


552 285 


158 681 


34 ; 




2 


22 


57 


37 


34 


105 (56 


48 


167 104 


64 


259 149 


89 


354 


110 


463 


265 


134 


587 -339 


161 725 


414 




3 


23 


60 


12 


35 


110 . 7-1 


50 


176 116 


66 


271 168 


91 


371 228 


113 


486 


!!.. 


137 


618 383 


164 764 


166 


30 


1 


20 


62 




31 


113 


45 


181 


60 


2! 


83 


391 


103 


512 


238 


125 


649 305 


151 802 


372 




2 


21 


64 


VI 


33 


1 18 ■ 


47 


190 


62 


299 


85 


4 


105 


535 


282 


129 


679 (60 


155 840 


139 




3 


22 


66 


44 


34 


123 79 


48 


198 


64 


309 1 78 


88 


423 .212 


108 


555 


'.17 


132 


706 405 


158 874 


194 


50 


1 


19 


71 


36 


30 


1 


43 


216 


57 


349 145 


78 


477 197 


97 


627 


j-.: 


120 


797 330 


144 984 


403 




2 


21 


73 


13 


32 


137 7(i 


45 


223 .119 


59 


3! 


81 


4 


100 


645 


V,<i 


123 


820 392 


148 1014 


478 




3 


22 


75 


48 


33 


141 86 


46 


229 


61 


31 


83 


502 263 


103 


661 


3-13 


126 


842 ill 


151 1043 


338 


100 


1 


18 


82 


.":'" 


28 


158 .6.0 


40 


262 


53 


442 i 50 


73 


611 204 


91 


810 


266 


112 


1038 341 


135 1285 


•11" 




2 


19 


83 


44 


30 


161 


42 


267 ..' . 


55 


447 178 


75 


619 


94 


822 


316 


115 


1054 405 


139 1306 


V>\ 




3 


20 


84 


511 


31 


163 89 


44 


272 138 


57 


4! 


78 


627 .". 


97 


834 


355 


118 


1069 455 


142 1327 


555 



Common Vent Capacity 













Type B Double-Wall Common Vent Diameter — D 


in.) 












4 


5 


6 


7 


8 


9 


10 


Vent 

Height 

H 










Combined Appliance Input Rating in Thousands of Btu 


>er Hour 










FAN 


FAN 


NAT 


FAN FAN 


NAT 


FAN FAN NAT 


FAN FAN -■ 


FAN FAN 


NAT 


FAN 


FAN 


NAT 


FAN 


FAN NAT 


(ft) 


+FAN 


+NAT -v ■. ■• 


+FAN +NAT 


♦NAT 


+FAN +NAT +NA1 


+FAN t\\l ■ 


+FAN +NAT 


,NAf 


+FAN +NAT 


■V\l 


+FAN 


+NAT ■ +NAT ' 


6 


92 


81 


65 


140 116 


KM 


204 161 1 17 


309 248 


404 314 


260 


547 


434 


335 


672 


520 410 ' 


8 


101 


90 


73 


155 129 


U4 : . 


224 178 163 


339 275 


444 348 


2-i0 


602 


480 


;:s 


740 


577 465 


10 


110 


97 


7" 


169 141 


124 


_•!■. I'H 178 


367 299 


477 377 


315 


649 


522 


405 


800 


627 495 


15 


125 


112 


Ml 


195 164 


'I'M - . 


283 228 206 


427 352 


556 444 


3n5 


753 


612 


•;■'... 


924 


733 56r> 


20 


136 


123 


102 


215 183 


160 


314 255 229 


475 394 


621 499 


405 


842 


688 


FSSHf 


1035 


826 .640 


30 


152 


138 


us 


244 210 


185 


361 297 266 


547 459 


720 585 


170 


979 


808 


605 


1209 


975 740 


50 


167 


153 


134 


279 244 


211 


421 353 310 


641 547 


854 706 


550 


1164 


977 


-..'. 


1451 


1188 860 


100 


175 


163 


NA 


31 1 277 


NA 


489 421 NA 


751 658 


1025 873 


625 


1408 


1215 


WO 


1784 


1502 975 



2006 Edition 



ANSI Z223. 1-103 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-103 



Table 13.2(a) Continued 





Connector 

Rise 

R 

(ft) 
















Number of Appli 


ances: 


Two 


or More 












Appliance 


Type: 


Category I 




Appliance Vent Connection: 


Type 


B Double-Wall Connector 
















Type 


B Double-Wall Vent and Connector Diameter — D (in 


•) 












12 


14 


16 


18 


20 


22 


24 




Appliance Input Rating Limits in Thousands of Btu per Hour 


Height 
H 

(ft) 


FAN NAT. 


FAN S V I" 


FAN NA1 


FAN' NAT 


FAN 


NAT 
Max 


FAN INAT 


FAN 


NAT 


Min 


Max Max 


Min 


M;i\ M:i\ 


Min 


Max Max 


Min 


M.i\ M,i\ 


Min 


Max 


Min 


Max ^Max 


Min 


Max 


Max 


6 


2 
4 
6 


174 

180 

NA 


764 496 
897 616 

NA \ ■■. 


223 
230 

NA 


1046 653 

1231 827. 

NA \\ 


281 

287 
NA 


1371 853 
1617 1081 

NA -U 


346 
352 

NA 


1772 1080 

2069 1370 

NA NA 


NA 
NA 
NA 


NA \.\ 
NA NA 
NA NA 


NA 
NA 
NA 


NA: NA 
NA ; NA 
NA i-'.NA 


NA 

NA 
NA 


NA 
NA 
NA 


NA 

NA 
NA 


8 


2 

4 
6 


186 

192 
198 


822 516 
952 644 
1050 " ■.' 


238 
244 
252 


1126 696 
1307 884 
1115 1072 


298 
305 
313 


1478 910 
1719 1150 
1902 '1390 


365 
372 
380 


1920 115H 
2211 1160 
2434 1 11 


NA 
471 
478 


NA ' NA 
2737 1800 
•'.ills 2 ISO 


NA 
560 
568 


NA ;' NA 
3319 2180 
3665 [2640 


NA 
662 
669 


NA 
3957 
4373 


NA 
2590 
3130 


10 


2 

4 
6 


196 
201 
207 


870 ' .536 
997 664 
1095 ,"792 


249 
256 
263 


1195 730 
1371 92-1 
1509 1.118 


311 

318 
325 


1570 955 
1804 1205 
1989 1455 


379 
387 
395 


20-19 1205 
2332 1535 
2556 !■>'■. 


NA 
486 
494 


NA' NA 
2887 ' 1890 
3169 2290 


NA 
581 
589 


na r ;na 

3502 2280 
3849 12760 


NA 
686 
694 


NA 
4175 
4593 


NA 
2710 
3270 


15 


2 
4 
6 


214 
221 
228 


967 '■ 568 
1085 712 
1 181 - '856 


272 
279 

286 


1334 790 
1499 100t) 
1632 1""",: 


336 
344 
351 


1760 1030 
1978 1320 
2157 1610 


408 
416 
424 


2317 1305 
2579 1665 
27"l. ..'025 


NA 
523 
533 


NA NA 
3197 2060 
3470 2510 


NA 
624 
634 


NA; NA 
3881 ! ,2490 
4216 J3030 


NA 
734 
743 


NA 
4631 
5035 


NA 
2960 
3600 


20 


2 
4 
6 


223 
230 
237 


1051 596 
1162 718 
1253 , 900 


291 
298 
307 


1443 .840 
1597 1064 
1726 1288 


357 
365 
373 


1911 1095 
2116 1395 
2287 1695 


430 
438 
450 


2533 1385 
2778 1765 
2984 2115 


NA 
554 
567 


NA ,' 'NA 
3447 2180 
3708 26.5 


NA 
661 
671 


NA t ..NA 
4190 |2g30 
4511 '%i90- 


NA 
772 
785 


NA 
5005 
5392 


NA 
3130 
3790 


30 


2 
4 
6 


216 
223 
231 


1217 632 
1316 792 
1400 952 


286 
294 
303 


1664 910 
1802 1160 
1920 1 . ■:■ 


367 
376 
384 


2183 1190 
2366 1510 
2524 1830 


461 
474 
485 


2891 1540 
3110 1920 
3299 2 "4, 


NA 
619 
632 


NA NA 
3840 1236*5 
4080 2875 


NA 
728 
741 


NA NA 
4861 2860 
4976 ; 3480 


NA 
847 
860 


NA' 
5606 
5961 


NA 
3410 
4150 


50 


2 
4 
6 


206 
213 
221 


1479 689 
1561 860 
1631 1031 


273 
281 
290 


2023 1007 
21.19 1291 
224'2 1 '. . . 


350 
359 
369 


2659 1315 
2814 1685 
2951 2055 


435 
447 
461 


3548 1665 
3730 2135 
3893 - 


NA 
580 
594 


NA ! NA 
4601 2633 
4808 3208' 


NA 
709 
724 


NA NA 
5569 f3185. 

5826 : 3885:' 


NA 
851 
867 


NA 
6633 
6943 


NA 
3790 
4620 


100 


2 
4 
6 


192 

200 
208 


1923 ! 712 
1984 888 
2035 1064 


254 
263 
272 


2644 1050 
2731 1346 
2811 1642 


326 
336 
346 


3490 1370 
3606 1760 
3714 2150 


402 
414 
426 


4707 1740 
4842 222U 
4968 2700 


NA 
523 
539 


NA :.; NA 
5982 '2750 
6143 3350 


NA 
639 
654 


NA .' NA 
7254 3330 
7453 :4070 


NA 
769 
786 


NA 
8650 
8892 


NA 
3950 
4810' 



Common Vent Capacity 





Type B Double-Wall Common Vent Diameter — D (in.) 




12 


14 


16 


18 


20 


22 


24 


Vent 

Height 

H 

(ft) 








Combined Appliance Input Rating in Thousands 


of Btu per Hour 










FAN 

+FAN 


FAN MAT 
+NAT +NAT 


FAN FAN 

+FAN +NAT 


NA1 

(-MAT 


FAN FAN * ■ 
+FAN +NAT \ VI 


FAN 

+FAN 


FAN \\l 

+NAT +NA1 


FAN FAN NAT 

+FAN +NAT ' +NA1' 


FAN 

+FAN 


FAN NAT 

+NAT +NAT 


FAN 
+FAN 


FAN ! 
+NAT ! 


NAT ; 

+NAT 


6 
8 
10 
15 
20 
30 
50 
100 


900 
994 
1076 
1247 
1405 
1658 
2024 
2569 


696 588 

773 ' , 652 

841 . 712 

986 ■ 825 

1116 916 

1327 1025 

1640 1280 

2131 ' 1670 


1284 
1423 
1542 
1794 
2006 
2373 
2911 
3732 


990 
1103 
1200 
1410 
1588 
1892 
2347 
3076 


SI5 
912 
99.5 

1 1 Of 

l.'.n 

1525 
1 -/. i 
2450 


1735 
1927 
2093 
2440 
2722 
3220 
3964 
5125 


1336 1065 
1491 1190 
1625 1300 
1910 1510 
2147 IbOO 
2558 1990 
3183 2430 
4202 3200 


2253 
2507 
2727 
3184 
3561 
4197 
5184 
6749 


1732 1315 
1936 1510 
2113 "1645 
2484 : 1910 
2798 2 HO 
3326 2520 
4149 "3075 
5509 4050 


2838 
3162 
3444 
4026 
4548 
5303 
6567 
8597 


2180 J"hi 
2439 .1.860 
2665 21'?.) 
3133 2360 
3552 2040 
4193' 3 HO 
5240 ! 3800 
6986 5000 


3488 
3890 
4241 
4971 
5573 
6539 
8116 
10,681 


2677 1970 
2998 ' 2200 
3278 ' 2400 
3862 2790 
4352 3120 
5157 -3680 
6458 \ 4500 
8648 5920 


4206 
4695 
5123 
6016 
6749 
7940 
9837 
13,004 


3226 i 
3616 1 
3957 
4670 ; 
5261 
6247 
7813 ! 
10,499 ; 


2390 
2680 
2920 
3400 
3800 
4480 
5475 
7200 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



54-104 



NATIONAL FUEL GAS CODE 



ANSI Z223. 1-104 



Table 13.2(b) Type B Double-Wall Vent 



Number of Appliances: 



Appliance Type: 



Appliance Vent Connection: 



Two or More 



Category I 



Single-Wall Metal Connector 



Vent Connector Capacity 





















Single- Wall Metal Vent Connector Diameter 


-D(in.) 












3 


4 


5 


6 


7 


8 


9 


10 




Appliance Input Rating Limits in Thousands of Btu per Hour 


Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


NAT 


FAN 


NAT 


FAN NAT 


FAN Wl 


FAN 


- 
Max 


FAN 


NAT 

Max 


FAN 


NAT 

Max! 


FAN NAT 


Min 


Max 


fiH 


Min 


Max 


Max 


Min 


Max \ia\ 


Min 


M:i\ Ma\ 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max Max 


6 


1 


NA 


NA 


.'li 


NA 


NA 




NA 


NA 71 


NA 


NA 102 


207 


223 


1 Id 


262 


293 


IS. 


325 


373 




447 


A'.: 286 




2 


NA 


NA 


B tt 


NA 


NA 


55 


NA 


NA 85 


168 


182 123 


215 


251 


167 


271 


331 


219- 


334 


422 




458 


524 344 




3 


NA 


NA 


:34; 


NA 


NA 


'»'•!■ 


121 


131 


175 


198 138 


222 


273 


188 


279 


361 




344 


462 


310 


468 


574 - 385 


8 


1 


NA 


NA 


27 


NA 


NA 




NA 


NA 75 


NA 


NA 106 


226 


240 


]45 


285 


316 


i 11 


352 


403 


'244 


481 


502 299: 




2 


NA 


NA 


'mf 


NA 


NA 


r,7 


125 


126 89 


184 


193 127 


234 


266 


173 


293 


353 


225 


360 


450 


2-2 


492 


560 355 




3 


NA 


NA 


35 


NA 


NA 


01.. 


130 


138 UK) 


191 


208 141 


241 


287 


197 


302 


381 


256 


370' 


489 


328 


501 


609 400 


10 


1 


NA 


NA 


28 


NA 


NA 


50 


119 


121 -77' : 


182 


186 


240 


253 


150 


302 


335 


19i. 


372 


429 


252 


506 


534 '308.^ 




2 


NA 


NA 


33 


84 


85 


59 


124 


134 91 


189 


203 1 12 


248 


278 


i S3 


311 


369 


235 


381 


473 


'302; 


517 


589 36t 




3 


NA 


NA 


% 


89 


91 


iiffili 


129 


144 102 


197 


217 148 


257 


299 


203 


320 


398 


205 


391 


511 


339 


528 


637 413 


15 


1 


NA 


NA 


29 


79 


87 


52 


116 


138 "-HV 


177 


214 116 


238 


291 


158 


312 


380 


...,-, 


397 


482 


2(.l. 


556 


596 324 




2 


NA 


NA 


34 


83 


94 


,.;> 


121 


150 .. 97 


185 


230 1 38 


246 


314 


189 


321 


411 


21* 


407 


522 


317 


568 


646 387 




3 


NA 


NA 


■f«i 


87 


100 


/() 


127 


160 109 


193 


243 157 


255 


333 




331 


438 


281 


418 


557 


.'.'■>> 


579 


690 437 


20 


1 


49 


56 


31.1 


78 


97 


51 


115 


152 ■ : 


175 


238 120 


233 


325 


1 1..". 


306 


425 




390 


538 


27i. 


546 


664 336 




2 


52 


59 


.:■!(> 


82 


103 


61 


120 


163 101 


182 


252 1 14 


243 


346 


197 


317 


453 


259 


400 


574 


1331; 


558 


709 405 




3 


55 


62 


10 


87 


107 


72 


125 


172 ii 


190 


264 161 


252 


363 


223 


326 


476 


291 


412 


607 


„C.i 


570 


750 457 


30 


] 


47 


60 


•I 


77 


110 


57 


112 


175 S'l 


169 


278 129 


226 


380 


175 


296 


497 


2 in 


378 


630 


29'i 


528 


779 ■ '358' 




2 


51 


62 


37 


81 


115 


1.7 


117 


185 106 


177 


290 132 


236 


397 


2i * 


307 


521 


274 


389 


662 


349 


541 


819 ■ 425 




3 


54 


64 


42 


85 


119 


76 


122 


193 120 


185 


300 172 


244 


412 


':SW 


316 


542 


•.,,., 


400 


690 


i'U 


555 


855 482 


50 


1 


46 


69 


:;i 


75 


128 


<:0 


109 


207 96 


162 


336 137 


217 


460 


' l-HS ■ 


284 


604 


215 


364 


768 




507 


951 384 




2 


49 


71 


40 


79 


132 


V2- 


114 


215 1 


170 


345 161 


226 


473 


223 


294 


623 


29 5 


376 


793 


.'.75 


520 


983 , 458 




3 


52 


72 


4.) 


83 


136 


82 


119 


221 123 


178 


353 180 


235 


486 


252 


304 


640 


v-.| 


387 


816 




535 


1013 518 


100 


1 


45 


79 


34 


71 


150 


61 


104 


249 ' 98 


153 


424 ' 140 


205 


585 


"l92 


269 


774 


21" 


345 


993 


1121 


476 1236 39 1 




2 


48 


80 


■■,;[■ 


75 


153 


73 


110 


255 ; 115 


160 


428 167 


212 


593 


228 


279 


788 


•_•■)•, 


358 


1011 


383: 


490 


1259 469 




3 


51 


81 


11. 


79 


157 


85 


114 


260 129 


168 


433 19(1 


222 


603 


.^'" 


289 


801 


; vi 


368 


1027 


l-.l 


506 1280 527 



Common Vent Capacity 

















Type B Double-Wall Vent Diameter 


-fl(in.) 










4 


5 


6 


7 


8 


9 


10 


Vent 












C 


ombined Appliance Input Rating in Thousan 


ds of Btu per Hour 








H 


FAN 


FAN 1 


NVI 


FAN 


FAN i 


\M 


FAN FAN NAT 


FAN FAN NAI 


FAN FAN NAT 


FAN 


FAN 


NAT 


FAN 


FAN NAT 


(ft) 


+FAN 


+NAT 1 


♦ NAT 


fFAN 


+NAT 


\\T 


+FAN+NAT +NAT 


+FAN+NAT \\l 


fFAN+NAT +NAT 


fFAN 


+NAT 


+NAT 


fFAN+NAT +NAT 


6 


NA 


■• 


.64 


NA 


113 = 


•.■I 


200 158 1.44 


304 244 196 


398 310 257 


541 


429 


332 


665 


515 407 


8 


NA 


:-" 


; :'Ht.; 7; 


NA 


126 i 


'lit- 


218 173 159 


331 269 218 


436 342 285 


592 


473 


>:3 


730 


569 460 


10 


NA 


9-1 


..; 


163 


137 i 


I21i 


237 189 174 


357 292 m 


467 369 30 1 


638 


512 


398 


787 


617 487 


15 


121 


108 t 


fvS 


189 


159 j 


14" 


275 221 


■_"i" 


416 343 


544 434 357 


738 


599 


456 


905 


718 553 


20 


131 


118 


■ ' .t)H: 


208 


177 j 


...156' 


305 247 


M!223; 


463 383 


606 487 395 


824 


673 


512 


1013 


808 626 


30 


145 


132 


1.J.3 


236 


202 


ISM 


350 286 


J57 


533 446 


703 570 459 


958 


790 


593 


1183 


952 723 


50 


159 


145 


128 


268 


233 , 


208 


406 337 


29... 


622 529 


833 686 535 


1139 


954 


689 


1418 


1)57 838 


100 


166 


153 


■ -NA. 


297 


263 


\.\ 


469 398 


NA 


726 633 6 ; 


999 846 606 


1378 


1185 


>,, 


1741 


1459 948 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



ANSI Z223.1-105 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-105 



Table 13.2(c) Masonry Chimney 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Type B Double-Wall Connector 



Vent Connector Capacity 





Connector 

Rise 

R 

(ft) 
















Type B Double-Wall Vent Connector Diameter 


-D(m.) 


















3 


4 


5 


6 


7 


8 


9 


10 


Vent 

Height 

H 

(ft) 














Appliance Input Rating Limits 


in Thousands of Btu per Hour 














FAN 


NAT 
Max 


FAN 


NAT ! 
Max 


FAN NAT 


FAN 


NAT 
Mas 


FAN SfAT 


FAN 


NAT 
Max 


FAN 


NAT 
Max 


FAN 


NAT 


Min 


Max 


Min 


Max 


Min 


Max Max 


Min 


Max 


Min 


Max Max 


Min 


Max 


Min 


Max 


Min 


Max 


Max 


6 


1 


24 


33 


21 


39 


62 


40 


52 


106 i 67 


65 


194 


101 


87 


274 1 141 


104 


370 


201 


124 


479 


253 


145 


599 


319 




2 


26 


43 


'28 


41 


79 


52: 


53 


133 85 


67 


230 


124- 


89 


324 173 


107 


436 


23.2 


127 


562 


300 


148 


694 


378 




3 


27 


49 


34 


42 


92 


61. 


55 


155 | 97 


69 


262 


143 


91 


369 i 203 


109 


491 


270 


129 


633 


349 


151 


795 


439 


8 


1 


24 


39 


22 


39 


72 


' 4l' 


55 


117 , 09 


71 


213 


105: 


94 


304 -1-48 


113 


414 


210 


134 


539 


267 


156 


682 


335 




2 


26 


47 


,29 


40 


87 


53 


57 


140 j .86 


73 


246 


127 


97 


350 i 179 


116 


473 


240 


137 


615 


311 


160 


776 


394 




3 


27 


52 


34 


42 


97 


62' 


59 


159 ' 98 


75 


269 


145 


99 


383 ; 206 


119 


517 


276 


139 


672 


358 


163 


848 


452 


10 


1 


24 


42 


22 


38 


80 


42 


55 


130 L.-71 


74 


232 


108 


101 


324 j. J53 


120 


444 


216 


142 


582 


277 


165 


739 


348 




2 


26 


50 


-29 


40 


93 


54 


57 


153 , 87 


76 


261 


1293 


103 


366 184 


123 


498 


247 


145 


652 


321 


168 


825 


407 




3 


27 


55 


35 


41 


105 


63 


58 


170 I 100 


78 


284 


148' 


106 


397 j 209 


126 


540 


281 


147 


705 


366 


171 


893 


463 


15 


1 


24 


48 


; "23 


38 


93 


44" 


54 


154 | 74 


72 


277 


114. 


100 


384 f:164 


125 


511 


229 


153 


658 


297 


184 


824 


375 




2 


25 


55 


31 


39 


105 


55 


56 


174 i-,89 


74 


299 


134 


103 


419 ! 192 


128 


558 


260 


156 


718 


339 


187 


900 


432 




3 


26 


59 


35 


41 


115 


■ 64! 


57 


189 ; 102 


76 


319 


153 


105 


448 Igl5 


131 


597 


292 


159 


760 


382 


190 


960 


486 


20 


1 


24 


52 


. 24 


37 


102 


46 


53 


172 . 77 


71 


313 


119 


98 


437 ! 173 


123 


584 


239 


150 


752 


312 


180 


943 


397 




2 


25 


58 


31 


39 


114 


56'' 


55 


190 !*S91 


73 


335 


138' 


101 


467 199 


126 


625 


270. 


153 


805 


354 


184 


1011 


452 




3 


26 


63 


35 


40 


123 


65 


57 


204 ; .104 


75 


353 


157 


104 


493 i 222 


129 


661 


301 


156 


851 


396 


187 


1067 


505 


30 


1 


24 


54 


25 


37 


111 


48 1 


52 


192 - 82 


69 


357 


127 ! 


96 


504 |yj87 


119 


680 


255 


145 


883 


337 


175 


1115 


432 




2 


25 


60 


32 


38 


122 


58= 


54 


208i..; : 95 


72 


376 


145 


99 


531 j .209 


122 


715 


287 


149 


928 


378 


179 


1171 


484 




3 


26 


64 


36 


40 


131 


66 


56 


221 107 


74 


392 


i6s: 


101 


554 ' 233 


125 


746 


317, 


152 


968 


418 


182 


1220 


535 


50 


1 


23 


51 


25 


36 


116 


51 


51 


209 89 


67 


405 


143. 


92 


582 ! ; 213 


115 


798 


294 


140 


1049 


392 


168 


1334 


506 




2 


24 


59 


32 


37 


127 


61 ' 


53 


225 102 


70 


421 


16V 


95 


604 f?235 


118 


827 


326 


143 


1085 


433 


172 


1379 


558 




3 


26 


64 


:.?6 


39 


135 


69-1 


55 


237 j 115 


72 


435 


180 


98 


624 ! 260 


121 


854 


357 


147 


1118 


474 


176 


1421 


611 


100 


1 


23 


46 


: 24 


35 


108 


50 


49 


208 92 


65 


428 


\5§ 


88 


640 !'"237 


109 


907 


334 


134 


1222 


454 


161 


1589 


596 




2 


24 


53 


31 


37 


120 


60: 


51 


224 105 


67 


444 


174 


92 


660 1.260 


113 


933 


368 


138 


1253 


497 


165 


1626 


651 




3 


25 


59 


35 


38 


130 


68: 


53 


237 118 


69 


458 


193 


94 


679 1 ?285 


116 


956 


399 


141 


1282 


540 


169 


1661 


705 



Common Vent Capacity 















Minimum Internal Area of Masonry Chimney Flue (in 


- 2 ) 












12 


19 


28 


38 


50 


63 


78 


113 


Vent 


Combined Appliance Input Rating in Thousands of Btu per Hour 


Height 
H 


FAN 


FAN NAT 


FAN 


FAN [NAT 


FAN 


FAN NAT 


FAN 


FAN NAT 


FAN FAN (NAT' 


FAN 


FAN NAT 


FAN 


FAN 


NAT 


FAN 


FAN 


NAT 


(ft) 


hFAN- 


hNAT+NAT 


hFAN-t 


NAT+NAT 


hFANh 


NAT+NAT 


hFAN+NAT+NAT 


+FAN+NAT+NAT 


hFAN-t 


NAT+NAT 


hFANn 


-NAT-i 


NAT 


hFAN +FAN 


+NAT 


6 


NA 


74 ' 25 


NA 


119 . 46 


NA 


178 71 


NA 


257 103 


NA 351 i'. 143. 


NA 


458 j 188 


NA 


582 


246 


1041 


853 


NA 


8 


NA 


80 ".' 28 


NA 


130 53 


NA 


193 82 


NA 


279 ': 119 ; 


NA 384 j '163' 


NA 


501 218 


724 


636 


278 


1144 


937 


408 


10 


NA 


84 i-'. 31 


NA 


138 : 56 


NA 


207 90 


NA 


299 131 


NA 409 1 177 


606 


538 236 


776 


686 


302 


1226 


1010 


454 


15 


NA 


NA 36 


NA 


152 67 


NA 


233 : 106 


NA 


334 ; 152 


523 467 [::2J2: 


682 


611 : 283 


874 


781 


365 


1374 


1156 


546 


20 


NA 


NA | . 41 


NA 


NA ' 75 


NA 


250 , 122 


NA 


368 172 


565 508 U 243 


742 


668 325 


955 


858 


419 


1513 


1286 


648 


30 


NA 


NA NA 


NA 


NA j NA 


NA 


270 ; 137 


NA 


404 198' 


615 564 278 


816 


747 s 381 


1062 


969 


496 


1702 


1473 


749 


50 


NA 


NA j: NA 


NA 


NA ; NA 


NA 


NA NA 


NA 


na; NA 


NA 620 [ 328 


879 


831 461 


1165 


1089 


606 


1905 


1692 


922 


100 


NA 


NA NA 


NA 


NA NA 


NA 


NA: NA 


NA 


na ; . na: 


NA NA - .348 


NA 


NA 499 


NA 


NA 


669 


2053 


1921 


1058 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



54-106 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-106 



Table 13.2(d) Masonry Chimney 





Number of Appliances: 


Two or More 




Appliance Type: 


Category I 




Appliance Vent Connection: 


Single-Wall Metal Connector 



Vent Connector Capacity 





















Single-Wall Metal Vent Connector Diameter - 


-D(in.) 












3 


4 


S 


6 


7 


8 


9 


10 
















Appliance Input Rating Limits 


in Thousands of Btu per Hour 








Height 
H 

(ft) 


Rise 
R 

(ft) 


FAN 


NAT 
Max 


FAN 


NA1 
Max 


FAN 


NAT 

Max; 


FAN NAT 


FAN 


NAT 


FAN 


NAT 


FAN 


NAT 


FAN NAT 


Min 


Max 


Min 


Max 


Min 


Max 


Min 


Max Max 


Min 


Max 


Min 


Max 


Min 


Max 


Mav 


Min 


Max ; Max 


6 


1 


NA 


NA 


21 


NA 


NA 


39 


NA 


NA 


66 


179 


191 i 100 


231 


271 


140 


292 


366 


200 


362 


474 


252 


499 


594 : 316 




2 


NA 


NA » 


28 


NA 


NA 


52 


NA 


NA 


- 


186 


227 123 


239 


321 


172 


301 


432 


231 


373 


557 


299 


509 


696 '■ '376 




3 


NA 


NA 


34 


NA 


NA 


61 


134 


153 


97, 


193 


258 142 


247 


365 


202 


309 


491 


J69 


381 


634 


348 


519 


793 437 


8 


1 


NA 


NA 


"I 


NA 


NA 


40 


NA 


NA 


' 68 


195 


208 103 


250 


298 


146 : 


313 


407 


207 


387 


530 


263 


529 


672 : 331 




2 


NA 


NA) 


28 


NA 


NA 


52 


137 


139 


85 


202 


240 ' 125 


258 


343 


177 


323 


465 


23S 


397 


607 


309 


540 


766 391 




3 


NA 


NA 


il 


NA 


NA 


62 


143 


156 


98 


210 


264 145 


266 


376 


205 


332 


509 


274 


407 


663 


356 


551 


838 : 450 


10 


1 


NA 


NA 


22 


NA 


NA 


41 


130 


151 


70 


202 


225 106 


267 


316 


151 


333 


434 


213 


410 


571 


273 


558 


727 ; ,:343 




2 


NA 


NA 


. 


NA 


NA 


53 


136 


150 


86 


210 


255 ; 128 


276 


358 


181 


343 


489 


244 


420 


640 


317 


569 


813 : 403 




3 


NA 


NA 


34 


97 


102 


62 


143 


166 


99, 


217 


277 J 147 


284 


389 


207 


352 


530 


: 279 


430 


694 


363 


580 


880 : .459 


15 


1 


NA 


NA 


23 


NA 


NA 


43 


129 


151 


73 


199 


271 ! 112 


268 


376 


161 


349 


502 


225 


445 


646 


291 


623 


808 : 366 




2 


NA 


NA 


30 


92 


103 


54 


135 


170 


88 


207 


295 ■ 132 


277 


411 


■ 189. 


359 


548 


256 


456 


706 


334 


634 


884 424 




3 


NA 


NA 




96 


112 




141 


185 


101 


215 


315 151 


286 


439 


213 


368 


586 


289 


466 


755 


378 


646 


945 , '479 


20 


1 


NA 


NA 


23 


87 


99 


<ir. 


128 


167 


76 


197 


303 1 . 11,7 


265 


425 


169 


345 


569 


235 


439 


734 


306 


614 


921 .387 




2 


NA 


NA 


30 


91 


111 


55' 


134 


185 


yo 


205 


325 i 36 


274 


455 


195' 


355 


610 


266 


450 


787 


348' 


627 


986 , 443 




3 


NA 


NA 


35 


96 


119 


,64 


140 


199 


103 


213 


343 ; 154 


282 


481 


219, 


365 


644 


298 


461 


831 


39] ; 


639 


1042 ■ 496 


30 


1 


NA 


NA 


24 


86 


108 


"47 


126 


187 


" 80 


193 


347 ! 124 


259 


492 


183' 


338 


665 


250 


430 


864 


330' 


600 


1089 ! 421 




2 


NA 


NA 


31 


91 


119 


57 


132 


203 


93 


201 


366 : 142 


269 


518 


205 


348 


699 


282 


442 


908 


372 


613 


1145 473 




3 


NA 


NA 


35 


95 


127 


tb 


138 


216 


105 


209 


381 160 


277 


540 


229 


358 


729 


312 


452 


946 


412- 


626 


1193 524 


50 


1 


NA 


NA 


21 


85 


113 


50- 


124 


204 


S7 


188 


392 139 


252 


567 


208 


328 


778 


287 


417 


1022 


383: 


582 


1302 ■ 492 




2 


NA 


NA 


: 31 


89 


123 


60 


130 


218 


100 


196 


408 ■ 158 


262 


588 


230 


339 


806 


320 


429 


1058 


425; 


596 


) 346 : 545 




3 


NA 


NA 


35 


94 


131 


68 


136 


231 


112 


205 


422 ' 176 


271 


607 


255 


349 


831 


351 


440 


1090 


466 


610 


1386 597 


100 


1 


NA 


NA 


23 


84 


104 


49 


122 


200 


> 89 


182 


410 1 151 


243 


617 


232 


315 


875 


328 


402 


1181 


444 


560 


1537 i 580 




2 


NA 


NA 


SO 


88 


115 


, ,59 


127 


215 


102 


190 


425 169 


253 


636 


254 


326 


899 


361 


415 


1210 


488 


575 


1570 634 




3 


NA 


NA 


: 34 


93 


124 


67 


133 


228 


,115 


199 


438 188 


262 


654 


279 


337 


921 


392 


427 


1238 


529 


589 


1604 i 687 



Common Vent Capacity 

















Minimum Internal Area of 


Masonry Chimney Flue (in 


• 2 ) 












12 


19 


28 


38 


50 


63 


78 


113 


Vent 














Combined Appliance Input Rat 


ng in Thousands of Btu pc 


r Hour 










H 


FAN 


FAN 


\\1 


FAN 


FAN NAT 


FAN 


FAN NAT 


FAN 


FAN [NAT, 


FAN FAN ?NATt 


FAN 


FAN *NAT 


FAN 


FAN 


NAT 


FAN 


FAN | 


NAT 


(ft) 


i-FAN 


t-NAT 


(•NAT 


i-FAN+NAT+NAT 


kFAN4 


NAT +NAT 


H-FAN4 


NAT+NAT 


hFAN +NAT +NAT' 


hFAN +NAT +NAT 


vTANi 


►NAT+NAT 


i-FAN +FAN 


+NAT 


6 


NA 


NA 


25 


NA 


118 45 


NA 


176 71 


NA 


255 j 102 


NA 348 >>142i 


NA 


455 i.:i87 


NA 


579 


245 


NA 


846 > 


NA 


8 


NA 


NA 


28 


NA 


128 52 


NA 


190 81 


NA 


276 1 11s: 


NA 380 f 162: 


NA 


497 : 217 


NA 


633 


277 


1136 


928 ; 


405 


10 


NA 


NA 


51 


NA 


136 56 


NA 


205 89 


NA 


295 129 


NA 405 i, 175| 


NA 


532 234 


771 


680 


30,0 


1216 


1000 I 


,,450 


15 


NA 


NA 


36 


NA 


NA 66 


NA 


230 105 


NA 


335 : 150 


NA 400 [- 210 


677 


602 280 


866 


772 


360 


1359 


1139 , 


540 


20 


NA 


NA 


' NA 


NA 


NA 74 


NA 


247 , 120 


NA 


362 1 170 


NA 503 : 240 


765 


661 321 


947 


849 


115 


1495 


1264 


640 


30 


NA 


NA 


NA 


NA 


NA NA 


NA 


NA 135 


NA 


398 | 195 


NA 558 ; 275 


808 


739 377 


1052 


957 


49(1 


1682 


1447 i 


740 


50 


NA 


NA 


NA 


NA 


NA "NA 


NA 


NA NA 


NA 


NA| NA 


NA 612 l 325 


NA 


821 : 456 


1152 


1076 


600 


1879 


1672 ' 


910 


100 


NA 


NA 


NA 


NA 


NA NA 


NA 


NA NA 


NA 


NA 1 NA 


NA NA 1, NA, 


NA 


NA 494 


NA 


NA 


663 


2006 


1885 ' 


1046 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



ANSIZ223.1-107 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-107 



Table 13.2(e) Single-Wall Metal Pipe or Type B Asbestos Cement Vent 



Vent Connector Capacity 



Number of Appliances: 



Appliance Type: 



Appliance Vent Connection: 



Two or More 



Draft Hood-Equipped 



Direct to Pipe or Vent 



Total Vent Height 
H 

(ft) 



Connector 
Rise 

R 

(ft) 



Vent Connector Diameter — D (in.) 



Maximum Appliance Input Rating in Thousands of Btu per Hour 



6-8 



Total Vent Height 
H 

(ft) 



21 
28 
34 



40 
53 
61 



68 
86 



102 
124 
147 



146 
178 
204 



Common Vent Diameter — D (in.) 



10 



Combined Appliance Input Rating in Thousands of 
Btu per Hour 



205 
235 
275 





1 


23 


44 


77 


117 


179 


240 


15 


2 


30 


56 


92 


134 


194 


265 




3 


35 


64 


102 


155 


216 


298 




1 


25 


49 


84 


129 


190 


270 


30 


2 


31 


58 


97 


145 


211 


295 


and up 


3 


36 


68 


107 


164 


232 


321 


Common Vent Capacity 



12 



10 
15 
20 
30 
50 



48 


78 


111 


155 


205 


320 


NA 


55 


89 


128 


175 


234 


365 


505 


59 


95 


136 


190 


250 


395 


560 


71 


115 


168 


228 


305 


480 


690 


80 


129 


186 


260 


340 


550 


790 


NA 


147 


215 


300 


400 


650 


940 


NA 


NA 


NA 


360 


490 


810 


1190 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 
Note: See Figure G.l (f) and Section 13.2. 



Table 13.2(f) Exterior Masonry Chimney 








Number of Appliances: 


Two or More 




Appliance Type: 


NAT + NAT 




Appliance Vent Connection: 


Type B Double-Wall 
Connector 







SPECIAL USE: 


Combined Appliance 


Maximum 


Input Rating in 


Thousands of Btu per 


Hour* 






Vent 
Height 








Internal Area of 


Chimney (ir 


• 2 ) 








H 

(ft) 


12 


19 


28 




38 






50 


63 


78 


113 


6 


25 


46 


71 




103 






143 


188 


246 


NA 


8 


28 


53 


82 




119 






163 


218 


278 


408 


10 


31 


56 


90 




131 






177 


236 


302 


454 


15 


NA 


67 


106 




152 






212 


283 


365 


546 


20 


NA 


NA 


NA 




NA 






NA 


325 


419 


648 


30 


NA 


NA 


NA 




NA 






NA 


NA 


496 


749 


50 


NA 


NA 


NA 




NA 






NA 


NA 


NA 


922 


100 


NA 


NA 


NA 




NA 






NA 


NA 


NA 


NA 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



54-108 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-108 



Table 13 


. 2 (g) Exterior Masonry Chimney 
























Numbei 


of Appliances: 


Two or 


More 




Appliance 


Type: 


NAT + 


NAT 




Appliance 


Vent Connection: 


Type B Double-Wall 
Connector 




SPECIAL' USE: Minimum Allowable Input Rating of Space-Heating Appliance in 


Iliousanris of Blu per Hour 




Vent 
Height 






Internal Area of Chimney (in 


■ 2 ) 








H 

(ft) 


12 


19 


28 


38 


50 




63 


78 


113 


6 








Local 99% winter design temperature: 37°F or greater 






NA 


8 




























10 




























15 


NA 

























20 


NA 


NA 


NA 


NA 


NA 




184 








30 


NA 


NA 


NA 


NA 


NA 




393 


334 





50 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


579 


100 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


6 








Local 99% 

68 


winter design temperature: 

NA NA 


27°F 


to 36°F 
180 


212 


NA 


8 








82 


NA 


NA 




187 


214 


263 


10 





51 


NA 


NA 


NA 




201 


225 


265 


15 


NA 


NA 


NA 


NA 


NA 




253 


274 


305 


20 


NA 


NA 


NA 


NA 


NA 




307 


330 


362 


30 


NA 


NA 


NA 


NA 


NA 




NA 


445 


485 


50 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


763 


100 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


6 


NA 


NA 


Local 99% 

NA 


winter design temperature: 

NA NA 


17°F 


to 26°F 

NA 


NA 


NA 


8 


NA 


NA 


NA 


NA 


NA 




NA 


264 


352 


10 


NA 


NA 


NA 


NA 


NA 




NA 


278 


358 


15 


NA 


NA 


NA 


NA 


NA 




NA 


331 


398 


20 


NA 


NA 


NA 


NA 


NA 




NA 


387 


457 


30 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


581 


50 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


862 


100 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


6 


NA 


NA 


Local 99% 

NA 


winter design temperature 

NA " NA 


5°F 


to 16°F 

NA 


NA 


NA 


8 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


10 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


430 


15 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


485 


20 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


547 


30 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


682 


50 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 


100 


NA 


NA 


NA 


NA 


NA 




NA 


NA 


NA 




Local 99% winter design temperature: 4°F or lower 
Not recommended for any vent configurations 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW, °C = (°F - 32)/1.8. 
Note: See Figure G.2.4 for a map showing local 99 percent winter design temperatures in the United States. 



2006 Edition 



ANSIZ223.1-109 



SIZING OF CATEGORY I VENTING SYSTEMS 



54-109 



Table 13.2(h) Exterior Masonry Chimney 



Number of Appliances: 



Appliance Type: 



Appliance Vent Connection: 



Two or More 



FAN + NAT 



Type B Double-Wall 
Connector 





si 


'EC.IAL USE: Combined 


Appliance 


Maximum Input 


Rating in Thous.iuils of Btu per Bon/ 






Vent 
Height 








Internal Area oi 


Chimney (in. 2 ) 








H 

(ft) 


12 


19 


28 


38 


50 


63 


78 


113 


6 


74 


119 


178 


257 


351 


458 


582 


853 


8 


80 


130 


193 


279 


384 


501 


636 


937 


10 


84 


138 


207 


299 


409 


538 


686 


1010 


15 


NA 


152 


233 


334 


467 


611 


781 


1156 


20 


NA 


NA 


250 


368 


508 


668 


858 


1286 


30 


NA 


NA 


NA 


404 


564 


747 


969 


1473 


50 


NA 


NA 


NA 


NA 


NA 


831 


1089 


1692 


100 


NA 


NA 


NA 


NA 


NA 


NA 


NA 


1921 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 



2006 Edition 



54-110 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-110 



Table 13.2(i) Exterior Masonry Chimney 















Number of Appliances: 


Two or More 




Appliance Type: 


FAN + NAT 




Appliance 


Vent Connection: 


Type B Double-Wall Connector 




SPECIAL 


USE: Minimum AUo» 


aim- Inpul Nuling 


of Space-Heating Applianc 


i 1 .• II 


ytisfeods ''f Su: pw 1 lnur 




Vent 
Height 








Internal Area of 


Chimney (in 


• 2 ) 










H 

(ft) 


12 


19 


28 




38 


50 






63 


78 


113 


6 








Local 99% winter design temperature: 37°F or 



greater 










8 
































10 
































15 


NA 





























20 


NA 


NA 


123 




190 


249 






184 








30 


NA 


NA 


NA 




334 


398 






393 


334 





50 


NA 


NA 


NA 




NA 


NA 






714 


707 


579 


100 


NA 


NA 


NA 




NA 


NA 






NA 


NA 


1600 


6 








Local 99% 
68 


winter design temperature: 
116 156 


27°F to 36°F 


180 


212 


266 


8 








82 




127 


167 






187 


214 


263 


10 





51 


97 




141 


183 






210 


225 


265 


15 


NA 


111 


142 




183 


233 






253 


274 


305 


20 


NA 


NA 


187 




230 


284 






307 


330 


362 


30 


NA 


NA 


NA 




330 


319 






419 


445 


485 


50 


NA 


NA 


NA 




NA 


NA 






672 


705 


763 


100 


NA 


NA 


NA 




NA 


NA 






NA 


NA 


1554 


6 





55 


Local 99% 
99 


winter design temperature: 
141 182 


17°F to 26°F 


215 


259 


349 


8 


52 


74 


111 




154 


197 






226 


264 


352 


10 


NA 


90 


125 




169 


214 






245 


278 


358 


15 


NA 


NA 


167 




212 


263 






296 


331 


398 


20 


NA 


NA 


212 




258 


316 






352 


387 


457 


30 


NA 


NA 


NA 




362 


429 






470 


507 


581 


50 


NA 


NA 


NA 




NA 


NA 






723 


766 


862 


100 


NA 


NA 


NA 




NA 


NA 






NA 


NA 


1669 


6 


NA 


78 


121 


Local 99% 


winter design 
166 


emperature 
214 


5°Ftol6°F 


252 


301 


416 


8 


NA 


94 


135 




182 


230 






269 


312 


423 


10 


NA 


111 


149 




198 


250 






289 


331 


430 


15 


NA 


NA 


193 




247 


305 






346 


393 


485 


20 


NA 


NA 


NA 




293 


360 






408 


450 


547 


30 


NA 


NA 


NA 




377 


450 






531 


580 


682 


50 


NA 


NA 


NA 




NA 


NA 






797 


853 


972 


100 


NA 


NA 


NA 




NA 


NA 






NA 


NA 


1833 


6 


NA 


NA 


Local 99% 
145 


winter design temperature: 
196 249 


-10T 


to4°F 


296 


349 


484 


8 


NA 


NA 


159 




213 


269 






320 


371 


494 


10 


NA 


NA 


175 




231 


292 






339 


397 


513 


15 


NA 


NA 


NA 




283 


351 






404 


457 


586 


20 


NA 


NA 


NA 




333 


408 






468 


528 


650 


30 


NA 


NA 


NA 




NA 


NA 






603 


667 


805 


50 


NA 


NA 


NA 




NA 


NA 






NA 


955 


1003 


100 


NA 


NA 


NA 




NA 


NA 






NA 


NA 


NA 








Local 99% winter design temperature: - 
Not recommended for any vent con 


-11°F or lower 
igurations 







For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 , 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 

Note: See Figure G.2.4 for a map showing local 99 percent winter design temperatures in the United States. 



2006 Edition 



ANSIZ223.1-111 



ANNEX A 



54-111 



Annex A Explanatory Material 

Annex A is not a part of the requirements of this NFPA document 
but is included for informational purposes only. This annex contains 
explanatory material, numbered to correspond with the applicable text 
paragraphs. 

A. 1.5 The following sample ordinance is provided to assist a 
jurisdiction in the adoption of this code and is not part of this 
code. 

ORDINANCE NO. 



An ordinance of the [jurisdiction] adopting the [year] edition 
of NFPA 54/ ANSI Z223.1, National Fuel Gas Code, documents 
listed in Chapter 2 of that code; prescribing regulations govern- 
ing conditions hazardous to life and property from fire or explo- 
sion; providing for the issuance of permits and collection of fees; 

repealing Ordinance No. of the [jurisdiction] and all other 

ordinances and parts of ordinances in conflict therewith; provid- 
ing a penalty; providing a severability clause; and providing for 
publication; and providing an effective date. 

BE IT ORDAINED BY THE [governing body] OF THE [juris- 
diction]: 

SECTION 1 That the National Fuel Gas Code and documents 
adopted by Chapter 2, three (3) copies of which are on file 
and are open to inspection by the public in the office of the 
[jurisdiction 's keeper of records] of the [jurisdiction], are hereby 
adopted and incorporated into this ordinance as fully as if set 
out at length herein, and from the date on which this ordi- 
nance shall take effect, the provisions thereof shall be control- 
ling within the limits of the [jurisdiction]. The same are hereby 
adopted as the code of the [jurisdiction] for the purpose of 
prescribing regulations governing conditions hazardous to 
life and property from fire or explosion and providing for 
issuance of permits and collection of fees. 

SECTION 2 Any person who shall violate any provision of 
this code or standard hereby adopted or fail to comply there- 
with; or who shall violate or fail to comply with any order made 
thereunder; or who shall build in violation of any detailed 
statement of specifications or plans submitted and approved 
thereunder; or failed to operate in accordance with any certifi- 
cate or permit issued thereunder; and from which no appeal 
has been taken; or who shall fail to comply with such an order 
as affirmed or modified by or by a court of competent jurisdic- 
tion, within the time fixed herein, shall severally for each and 
every such violation and noncompliance, respectively, be 
guilty of a misdemeanor, punishable by a fine of not less than 

$ nor more than $ or by imprisonment 

for not less than 



days nor more than_ 



days or by both such fine and imprisonment. The imposition 
of one penalty for any violation shall not excuse the violation 
or permit it to continue; and all such persons shall be required 
to correct or remedy such violations or defects within a reason- 
able time; and when not otherwise specified the application of 
the above penalty shall not be held to prevent the enforced 
removal of prohibited conditions. Each day that prohibited 
conditions are maintained shall constitute a separate offense. 
SECTION 3 Additions, insertions, and changes — that the 
[year] edition of NFPA54/ANSI Z223.1, NationalFuel Gas Code, 
is amended and changed in the following respects: List 
Amendments 

. of [jurisdic- 



SECTION 4 That ordinance No, 



tion] entitled [fill in the title of the ordinance or ordinances in effect 
at the present time] and all other ordinances or parts of ordi- 
nances in conflict herewith are hereby repealed. 



SECTION 5 That if any section, subsection, sentence, 
clause, or phrase of this ordinance is, for any reason, held to 
be invalid or unconstitutional, such decision shall not affect 
the validity or constitutionality of the remaining portions of 
this ordinance. The [governing body] hereby declares that it 
would have passed this ordinance, and each section, subsec- 
tion, clause, or phrase hereof, irrespective of the fact that any 
one or more sections, subsections, sentences, clauses, and 
phrases be declared unconstitutional. 

SECTION 6 That the [jurisdiction 's keeper of records] is hereby 
ordered and directed to cause this ordinance to be published. 
[NOTE: An additional provision may be required to direct the 
number of times the ordinance is to be published and to 
specify that it is to be in a newspaper in general circulation. 
Posting may also be required.] 

SECTION 7 That this ordinance and the rules, regulations, 
provisions, requirements, orders, and matters established and 
adopted hereby shall take effect and be in full force and effect 
[time period] from and after the date of its final passage and 
adoption. 

A.3.2.1 Approved. The American Gas Association, American 
National Standards Institute, and the National Fire Protection 
Association do not approve, inspect, or certify any installa- 
tions, procedures, appliances, equipment, or materials; nor 
do they approve or evaluate testing laboratories. In determin- 
ing the acceptability of installations, procedures, appliances, 
equipment, or materials, the authority havingjurisdiction may 
base acceptance on compliance with NFPA or other appropri- 
ate standards. In the absence of such standards, said authority 
may require evidence of proper installation, procedure, or 
use. The authority havingjurisdiction may also refer to the 
listings or labeling practices (see 3.2.2.) of an organization that 
is concerned with product evaluations and is thus in a position 
to determine compliance with AGA, ANSI, CSA, NFPA, or ap- 
propriate standards for the current production of listed items. 
Additional information regarding the coordination of appli- 
ance design, construction, and maintenance can be found in 
Annex B. 

A.3.2.2 Authority Havingjurisdiction (AHJ). The phrase "au- 
thority having jurisdiction," or its acronym AHJ, is used in 
NFPA documents in a broad manner, since jurisdictions and 
approval agencies vary, as do their responsibilities. Where pub- 
lic safety is primary, the authority havingjurisdiction may be a 
federal, state, local, or other regional department or indi- 
vidual such as a fire chief; fire marshal; chief of a fire preven- 
tion bureau, labor department, or health department; build- 
ing official; electrical inspector; or others having statutory 
authority. For insurance purposes, an insurance inspection de- 
partment, rating bureau, or other insurance company repre- 
sentative may be the authority having jurisdiction. In many 
circumstances, the property owner or his or her designated 
agent assumes the role of the authority havingjurisdiction; at 
government installations, the commanding officer or depart- 
mental official may be the authority havingjurisdiction. 

As used in the definition of Authority Havingjurisdiction, 
equipment includes appliances and materials. 

A3.2.4 Listed. The means for identifying listed appliances 
and equipment may vary for each organization concerned 
with product evaluation; some organizations do not recognize 
appliances and equipment as listed unless it is also labeled. 
The authority havingjurisdiction should utilize the system em- 
ployed by the listing organization to identify a listed product. 
As used in the definition of Listed, equipment includes 
appliances and materials. 



2006 Edition 



54-112 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-112 



A.3.3.6.11.1 Category I Vented Appliance. For additional in- 
formation on appliance categorization as shown in 3.3.6.11.1 
through 3.3.6.11.4, see the appropriate Z21 and Z83 American 

National Standards. 

A.3.3.98.7 Venting System. A venting system is usually com- 
posed of a vent or a chimney and vent connector(s), if used, 
assembled to form the open passageway. 

A.5.4. 1 The size of gas piping depends on the following factors: 

( 1 ) Allowable loss in pressure (see 5. 4. 4) from point of delivery 
to appliance 

(2) Maximum gas demand 

(3) Length of piping and number of fittings 

(4) Specific gravity of the gas 

(5) Diversity factor 

(6) Foreseeable future demand 

A.5.4.2 To obtain the cubic feet per hour of gas required, 
divide the Btu per hour rating by the Btu per cubic foot heat- 
ing value of the gas supplied. The heating value of the gas can 
be obtained from the local gas supplier. 

Where the ratings of the appliances to be installed are not 
known, Table 5.4.2.1 shows the approximate demand of typi- 
cal appliances by types. 

A.5.4.3 Gas Piping Size. The gas-cariying capacities for differ- 
ent sizes and lengths of iron pipe, or equivalent rigid pipe, and 
semirigid tubing are shown in the capacity tables in Chapter 6. 

Table 6.2(a) through Table 6.2(t) indicate approximate ca- 
pacities for single runs of piping. If the specific gravity of the gas is 
other than 0.60, correction factors should be applied. Correction 
factors for use with these tables are given in Table C.3.4. 

For any gas piping system, for special appliances, or for 
conditions other than those covered by the capacity tables in 
Chapter 6, such as longer runs, greater gas demands, or 
greater pressure drops, the size of each gas piping system 
should be determined by the pipe sizing equations in Section 
6.4 or by standard engineering methods acceptable to the au- 
thority havingjurisdiction. 

A suggested procedure for using the Chapter 6 tables to 
size a gas piping system is illustrated in Annex C. 

A.5.5.1(l) For welding specifications and procedures that 
can be used, see the API 1104, Standard for Welding Pipelines and 
Related Facilities; AWS B2.1, Standard for Welding Procedure and 
Performance Qualification; or ASME Boiler and Pressure Vessel Code, 
Section IX. 

A.5.6.2.3 An average of 0.3 grains of hydrogen sulfide per 
100 scf (0.7 mg/100 L) is equivalent to a trace as determined 
by ANSI/ASTM D 2385, Method of Test for Hydrogen Sulfide and 
Mercaptan Sulfur in Natural Gas (Cadmium Sulfate — Iodometric 
Titration Method), or ANSI/ASTM D 2420, Method of Test for 
Hydrogen Sulfide in Liquefied Petroleum (LP) Gases (Lead Acetate 
Method). 

A.5.6.3.2 See A.5.6.2.3. 

Copper and brass tubing and fittings (except tin-lined cop- 
per tubing) should not be used if the gas contains more than 
an average of 0.3 grains of hydrogen sulfide per 100 scf of gas 
(0.7 mg/100 L). 

A.5. 6.4.2 The reference to UL 65 1 , Schedule 40 and Schedule 80 
Rigid PVC Conduit, is to require that PVC be a minimum of 
Schedule 40 and that it be resistant to the effects of ultraviolet 
light because it is likely to be exposed to the outdoors when 
used for regulator vents. 



A.5.6.8.1 For welding and brazing specifications and proce- 
dures that can be used, see API 1104, Standard for Welding Pipe- 
lines and Related Facilities; AWS B2.1, Standard for Welding Proce- 
dure and Performance Qualification; AWS B2.2, Standard fin- 
Brazing Procedure and Performance Qualification; or ASME Boiler 
and Pressure Vessel Code, Section IX. 

A.5.7 This section applies to premises-owned meters [see 
1.1.1.2(16)]. 

A.5.8 This section applies to premises-owned regulators [see 
1.1.1.2(16)]. 

A.6.1.1 Longest Length Method. The longest length method is 
the traditional method used to determine the equivalent pip- 
ing length L that is then used along with the pipe sizing tables 
to determine the appropriate pipe diameter size. 

A.6.1.2 Branch Length Method. This method is an alternate 
sizing method that could permit slightly smaller pipe diam- 
eters in some segments of a piping system when compared 
with the longest length method. 

A.6.4.1 Low-Pressure Formula. The presented formula is the 
standard flow formula located in Annex C but rearranged to 
solve for the pipe diameter. 

A.6.4.2 High-Pressure Formula. The presented formula is the 
standard flow formula located in Annex C but rearranged to 
solve for the pipe diameter. 

A.7.1.3 For information on corrosion protection of under- 
ground pipe, see NACE RP 0169, Control of External Corrosion on 
Underground or Submerged Metallic Piping Systems. Information 
on installation, maintenance, and corrosion protection might 
be available from the gas supplier. 

A.7.1.4 The gas supplier can be consulted for recommenda- 
tions. 

A.7.2.5 It is the intent that gas piping, shutoff valves required 
by this code, and regulators be allowed to be installed in acces- 
sible portions of plenums, accessible ducts used to supply com- 
bustion and ventilation air in accordance with Section 5.3, and 
accessible spaces between a fixed ceiling and dropped ceiling. 

A.7.4.3 Only vertical chases are recognized by the coverage. 
It is believed that welded joints for a horizontal gas line would 

be preferable to a horizontal chase. 

i 

A.7.12.4 The mixing blower is acknowledged as a special case 
because of its inability to tolerate control valves or comparable 
restrictions between mixing blower and burner(s). With these 
limitations, mixing blower installations are not required to utilize 
safety blowouts, backfire preventers, explosion heads, flame ar- 
resters, or automatic firechecks that introduce pressure losses. 

A.7. 12.5.1 For information on venting of deflagrations, see 
NFPA 68, Guide for Venting of Deflagrations. 

A.7. 12.5.4 Additional interlocks might be necessary for safe 
operation of appliances supplied by the gas-mixing machine. 

A.7. 12.6(1) Two basic methods are generally used. One calls for 
a separate firecheck at each burner, the other a firecheck at each 
group of burners. The second method is generally more practical 
if a system consists of many closely spaced burners. 

An approved automatic firecheck should be installed as near 
as practical upstream from a flame arrester used for local protec- 
tion where test burners or lighting torches are employed. 



2006 Edition 



ANSIZ223.1-113 



ANNEX A 



54-113 



A.8.1.1 Because it is sometimes necessary to divide a piping 
system into test sections and install test heads, connecting pip- 
ing, and other necessary appurtenances for testing, it is not 
required that the tie-in sections of pipe be pressure-tested. 
Tie-in connections, however, should be tested with a noncor- 
rosive leak detection fluid after gas has been introduced and 
the pressure has been increased sufficiently to give some indi- 
cations whether leaks exist. 

The test procedure used should be capable of disclosing all 
leaks in the section being tested and should be selected after 
giving due consideration to the volumetric content of the sec- 
tion and to its location. 

Under no circumstances should a valve in a line be used as a 
bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, unless two valves are installed 
in series with a valved "telltale" located between these valves. A 
valve should not be subjected to the test pressure unless it can be 
determined that the valve, including the valve closing mecha- 
nism, is designed to safely withstand the test pressure. 

A.8. 1.4.3 During pressure tests conducted over long periods 
of time, such as overnight, the effects of temperature on pres- 
sure should be considered. Temperature drops can cause a 
drop in pressure great enough to be indicated by the test 
gauge. These temperature drops may cause test evaluators to 
think that a leak exists in the piping system when in fact the 
pressure drop was caused by a decrease in the ambient tem- 
perature. See Example 5 in C.8.5. 

A.8.2.3 See Annex D for a suggested method. 

A.8.3 The process of purging a gas pipeline of fuel gas and 
replacing the fuel gas with air or charging a gas pipeline that is 
full of air with fuel gas requires that a significant amount of 
combustible mixture not be developed within the pipeline or 
released within a confined space. 

A.9.1.1 The American Gas Association, American National 
Standards Institute, and the National Fire Protection Associa- 
tion do not approve, inspect, or certify any installations, pro- 
cedures, appliances, equipment, or materials; nor do they ap- 
prove or evaluate testing laboratories. In determining 
acceptability of installations, procedures, appliances, equip- 
ment, or materials, the authority having jurisdiction can base 
acceptance on compliance with AGA, ANSI, CSA, or NFPA, or 
other appropriate standards. In the absence of such standards, 
said authority can require evidence of proper installation, pro- 
cedure, or use. The authority havingjurisdiction can also refer 
to the listings or labeling practices (see 3.2.3, Labeled, and 3.2.4, 
Listed) of an organization concerned with product evaluations 
and is thus in a position to determine compliance with appro- 
priate standards for the current production of listed items. 
Additional information regarding the coordination of appli- 
ance design, construction, and maintenance can be found in 
Annex B. 

A.9.1.6 Halogenated hydrocarbons are particularly injurious 
and corrosive after contact with flames or hot surfaces. 

A.9.3 Special Conditions Created by Mechanical Exhausting or 
Fireplaces. Operation of exhaust fans, ventilation systems, 
clothes dryers, or fireplaces can create conditions requiring 
special attention to avoid unsatisfactory operation of installed 
appliances. 

A.9.3.2.1 See Table A.9.3.2.1. 

A.9.3.2.2 See Table A.9.3.2.2(a) and Table A.9.3.2.2(b). 



Table A.9.3. 2. 1 Standard Method: Required 
Volume, All Appliances 



Appliance Input 


Required Volume 


(Btu/hr) 


(ft 3 ) 


5,000 


250 


10,000 


500 


15,000 


750 


20,000 


1,000 


25,000 


1,250 


30,000 


1,500 


35,000 


1,750 


40,000 


2,000 


45,000 


2,250 


50,000 


2,500 


55,000 


2,750 


60,000 


3,000 


65,000 


3,250 


70,000 


3,500 


75,000 


3,750 


80,000 


4,000 


85,000 


4,250 


90,000 


4,500 


95,000 


4,750 


100,000 


5,000 


105,000 


5,250 


110,000 


5,500 


115,000 


5,750 


120,000 


6,000 


125,000 


6,250 


130,000 


6,500 


135,000 


6,750 


140,000 


7,000 


145,000 


7,250 


150,000 


7,500 


160,000 


8,000 


170,000 


8,500 


180,000 


9,000 


190,000 


9,500 


200,000 


10,000 


210,000 


10,500 


220,000 


11,000 


230,000 


11,500 


240,000 


12,000 


250,000 


12,500 


260,000 


13,000 


270,000 


13,500 


280,000 


14,000 


290,000 


14,500 


300,000 


15,000 



A.9.3.2.3(l) See Figure A.9.3.2.3(l). 

A.9.3.3.1(l) SeeFigureA9.3.3.1(l)(a) andFigureA9.3.3.1(l)(b). 

A.9.3.3.1(2) See Figure A.9.3.3.1 (2). 

A.9.3.3.2 See Figure A.9.3.3. 2. 

A.9.6.6 For information on gas convenience outlets, see ANSI 
Z21.90-2001, Gas Convenience Outlets and Optional Enclosures. 



2006 Edition 



54-114 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-114 



Table A.9.3.2.2(a) Known Air Infiltration 
Rate Method, Minimum Space Volume for 
Appliances Other than Fan-Assisted, for Specified 
Infiltration Rates (ACH) 



Table A.9.3.2.2 (b) Known Air Infiltration 
Rate Method, Minimum Space Volume for 
Fan-Assisted Appliance, for Specified Infiltration 
Rates (ACH) 







Space 


Space 




Required 


Required 


Required 


Appliance 


Space 


Volume 


Volume 


Appliance 


Volume 


Volume 


Volume 


Input 


Volume 


0.30 ACH 


0.35 ACH 


Input 


0.25 ACH 


0.30 ACH 


0.35 ACH 


(Btu/hr) 


0.25 ACH (ft 3 ) 


(ft 3 ) 


(ft 3 ) 


(Btu/hr) 


(ft 3 ) 


(ft 3 ) 


(ft 3 ) 


5,000 


420 


350 


300 


5,000 


300 


250 


214 


10,000 


840 


700 


600 


10,000 


600 


500 


429 


15,000 


1,260 


1,050 


900 


15,000 


900 


750 


643 


20,000 


1,680 


1,400 


1,200 


20,000 


1,200 


1,000 


857 


25,000 


2,100 


1,750 


1,500 


25,000 


1,500 


1,250 


1,071 


30,000 


2,520 


2,100 


1,800 


30,000 


1,800 


1,500 


1,286 


35,000 


2,940 


2,450 


2,100 


35,000 


2,100 


1,750 


1,500 


40,000 


3,360 


2,800 


2,400 


40,000 


2,400 


2,000 


1,714 


45,000 


3,780 


3,150 


2,700 


45,000 


2,700 


2,250 


1,929 


50,000 


4,200 


3,500 


3,000 


50,000 


3,000 


2,500 


2,143 


55,000 


4,620 


3,850 


3,300 


55,000 


3,300 


2,750 


2,357 


60,000 


5,040 


4,200 


3,600 


60,000 


3,600 


3,000 


2,571 


65,000 


5,460 


4,550 


3,900 


65,000 


3,900 


3,250 


2,786 


70,000 


5,880 


4,900 


4,200 


70,000 


4,200 


3,500 


3,000 


75,000 


6,300 


5,250 


4,500 


75,000 


4,500 


3,750 


3,214 


80,000 


6,720 


5,600 


4,800 


80,000 


4,800 


4,000 


3,429 


85,000 


7,140 


5,950 


5,100 


85,000 


5,100 


4,250 


3,643 


90,000 


7,560 


6,300 


5,400 


90,000 


5,400 


4,500 


3,857 


95,000 


7,980 


6,650 


5,700 


95,000 


5,700 


4,750 


4,071 


100,000 


8,400 


7,000 


6,000 


100,000 


6,000 


5,000 


4,286 


105,000 


8,820 


7,350 


6,300 


105,000 


6,300 


5,250 


4,500 


110,000 


9,240 


7,700 


6,600 


110,000 


6,600 


5,500 


4,714 


115,000 


9,660 


8,050 


6,900 


115,000 


6,900 


5,750 


4,929 


120,000 


10,080 


8,400 


7,200 


120,000 


7,200 


6,000 


5,143 


125,000 


10,500 


8,750 


7,500 


125,000 


7,500 


6,250 


5,357 


130,000 


10,920 


9,100 


7,800 


130,000 


7,800 


6,500 


5,571 


135,000 


11,340 


9,450 


8,100 


135,000 


8,100 


6,750 


5,786 


140,000 


11,760 


9,800 


8,400 


140,000 


8,400 


7,000 


6,000 


145,000 


12,180 


10,150 


8,700 


145,000 


8,700 


7,250 


6,214 


150,000 


12,600 


10,500 


9,000 


150,000 


9,000 


7,500 


6,429 


160,000 


13,440 


11,200 


9,600 


160,000 


9,600 


8,000 


6,857 


170,000 


14,280 


11,900 


10,200 


170,000 


10,200 


8,500 


7,286 


180,000 


15,120 


12,600 


10,800 


180,000 


10,800 


9,000 


7,714 


190,000 


15,960 


13,300 


11,400 


190,000 


11,400 


9,500 


8,143 


200,000 


16,800 


14,000 


12,000 


200,000 


12,000 


10,000 


8,571 


210,000 


17,640 


14,700 


12,600 


210,000 


12,600 


10,500 


9,000 


220,000 


18,480 


15,400 


13,200 


220,000 


13,200 


11,000 


9,429 


230,000 


19,320 


16,100 


13,800 


230,000 


13,800 


11,500 


9,857 


240,000 


20,160 


16,800 


14,400 


240,000 


14,400 


12,000 


10,286 


250,000 


21,000 


17,500 


15,000 


250,000 


15,000 


12,500 


10,714 


260,000 


21,840 


18,200 


15,600 


260,000 


15,600 


13,000 


11,143 


270,000 


22,680 


18,900 


16,200 


270,000 


16,200 


13,500 


11,571 


280,000 


23,520 


19,600 


16,800 


280,000 


16,800 


14,000 


12,000 


290,000 


24,360 


20,300 


17,400 


290,000 


17,400 


14,500 


12,429 


300,000 


25,200 


21,000 


18,000 


300,000 


18,000 


15,000 


12,857 



For SI units, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 
Note: ACH = air change per hour. 



For SI units, 1 ft = 0.305 m, 1000 Btu per hr = 0.293 kW. 
Note: ACH = air change per hour. 



2006 Edition 



ANSIZ223.1-115 



ANNEX A 



54-115 



Chimney or gas vent 




!< — Opening 



Opening 



FIGURE A.9.3.2.3(l) All Combustion Air from Adjacent In- 
door Spaces through Indoor Combustion Air Openings. 



Chimney or gas vent 



Ventilation louvers 
(each end of attic) 




Inlet air duct 
[ends 1 ft (300 mm) 
above floor] 



I , I , I , I 



I I I I I I 



I , I , I , I 



III 



FIGURE A.9.3.3.1(l)(b) All Combustion Air from Outdoors 
through Ventilated Attic. 



Chimney or gas vent 



Ventilation louvers 
(each end of attic) 




Alternate 
air inlet - 



. Ventilation louvers for — 
unhealed crawl space 

FIGURE A.9.3.3.1(l)(a) All Combustion Air from Outdoors 
— Inlet Air from Ventilated Crawl Space and Outlet Air to 
Ventilated Attic. 



* 



-Chimney or gas vent 




inn 



TT 



Furnace 



Water 
heater 



Inlet air duct 



T~T 



III 



3zn 



TZJ 



III 



III 



I I I I I 



FIGURE A.9.3.3.1(2) All Combustion Air from Outdoors 
through Horizontal Ducts. 



2006 Edition 



54-116 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-116 



Chimney or gas vent 




Opening 



Alternate 
opening 
location 



FIGURE A.9.3.3.2 All Combustion Air from Outdoors 
through Single Combustion Air Opening. 



A10.1.2 Also see Prohibited Installations, 10.6.1, 10.7.1, 10.8.2, 
10.9.2, and 10.23.1. 

A.10.2.6 Reference can be made to NFPA90A, Standard for the 
Installation of Air-Conditioning and Ventilating Systems, or to 
NFPA 90B, Standard for the Installation of Warm Air Heating and 
Air-Conditioning Systems. 

A.10.3.6 For details of requirements on low-pressure heating 
boiler safety devices, refer to ASME Boiler and Pressure Vessel 
Code, Section IV, "Rules for Construction of Heating Boilers." 

A. 10.3.7.3 Reference can be made to NFPA 90A, Standard for 
the Installation of Air-Conditioning and Ventilating Systems, or to 
NFPA 90B, Standard for the Installation of Warm Air Heating and 
Air-Conditioning Systems. 

A.10.6.1 For information on decorative appliances for instal- 
lation invented fireplaces, see ANSI Z21.60/CGA2.26, Decora- 
tive Gas Appliances for Installation in Solid-Fuel Burning Fireplaces. 

A.10.7.1 For information on vented gas fireplaces, see ANSI 
Z21.50/CGA2.22, Vented Gas Fireplaces. 

A. 10.9.2.2 Recirculation of room air can be hazardous in the 
presence of flammable solids, liquids, gases, explosive materi- 
als (e.g., grain dust, coal dust, gun powder), and substances 
(e.g., refrigerants, aerosols) that can become toxic when ex- 
posed to flame or heat. 

A.10.12.8 Where exhaust fans are used for ventilation, pre- 
cautions might be necessary to avoid interference with the op- 
eration of the appliance. 

A10.23.1 It is recommended that space heating appliances 
installed in all bedrooms or rooms generally kept closed be of 
the direct vent type. (See Section 10.27.) 



A.10.28.7 A hole near the top of a cold water inlet tube that 
enters the top of the water heater or tank is commonly ac- 
cepted for this purpose. 

A.ll.1.1 It should be recognized that for most burners, the 
input rate can be changed only slightly by changing the input 
pressure. Burner input should be checked in accordance with 
the appliance manufacturer's installation instructions. If no 
appliance instructions are provided, burner input rate can be 
checked as follows: 



(1) 



Checking Burner Input Using a Meter (Clocking). To check the 
Btu/hr input rate, the test hand on the gas meter should 
be timed for at least one revolution and the input deter- 
mined from this timing. Test dials are generally marked 
Vi, 1, 2, or 5 ft 3 /revolution depending on the size of the 
meter. Instructions for converting the test hand readings 
to cubic feet per hour are given in Table A.ll.1.1. This 
table is provided for specific gas pressures within the 
meters and gives gas flow rate (corrected to standard con- 
ditions) in cubic feet of gas per hour. Standard tempera- 
ture is 60°F, and standard pressure is 29.92 inches of mer- 
cury. Measure the time for at least one revolution of a dial. 
Look up the gas flow rate in Table A.ll.1.1. Gas flow rates 
can be calculated for meter pressures other than in these 
tables in the following manner. A pressure adjustment fac- 
tor F should be determined for use in the gas input calcu- 
lation for the gas pressure difference AP between the 
meter inlet and the atmosphere. The gas supplier can 
provide the pressure at the meter inlet. The pressure ad- 
justment factor F is calculated with the following formula. 
Table A.ll.1.1 was calculated using this formula. 



F = 



AP + (£xl3.596) 
29.92x13.596 



where: 

F = the pressure correction factor 
AP = the meter inlet pressure (inches of water 
column) 
B = the barometric pressure, unadjusted to sea level 
(inches of mercury) 

NOAA weather reports barometric pressure in inches of 
mercury, adjusted to sea level. The sea level adjustment must 
be subtracted from the barometric pressure reported by 
NOAA weather. The local sea level adjustment can be 
obtained from NOAA. 

EXAMPLE: NOAA reported barometric pressure to be 
30.12 in. of mercury for a city at 250 ft elevation. The 
barometric pressure adjustment for 250 ft is 0.27 in. of mercury. 
Subtract the local sea level adjustment from the NOAA 
barometric pressure to get the unadjusted barometric pressure. 

30.12-0.27 = 29.85 

The gas flow rate £)is calculated using the following 
formula: 

Q = FxC 

where: 

gas flow rate at standard conditions (ft s /hr) 



Q 

F 

C 



the pressure adjustment factor 
the timed gas flow rate (ft 3 /hr) 



2006 Edition 



ANSIZ223.1-117 



ANNEX A 



54-117 



The gas input rate lis calculated with the following formula: 
I=QxHHV 



where: 
I = 

C = 

HHV = 



gas input rate (Btu/hr) 

the gas flow rate at standard conditions (ft 3 /hr) 

the average higher heat value of the gas at 

standard temperature and pressure conditions 

(Btu/ft 3 ), which can be obtained from the gas 

supplier 



Appliances can be seriously overtired if the timed meter 
gas flow rate used to set input rate is not adjusted for meter 
pressure. At 2 psi meter pressure, an appliance would be 
13 percent overfired if the gas flow rate is not adjusted for 
meter pressure. 

(2) Checking Burner Input by Using Orifice Pressure Drop and Ori- 
fice Size. The fixed orifice size for each burner can be de- 
termined in accordance with Table F.l (a) for utility gases 
and Table F.l (b) for undiluted liquefied petroleum gases. 



Table A. 11. 1.1 


Gas Flow Rate to Burner in Cubic Feet 


per Hour at Standard Temperature 




and Pressure 




















Size of Test Meter Dial 




Meter Pressure 






Meter Pressure 




Meter Pressure 




Seconds 


7.0 in. w.c. 


or 0.25 psi 


11.0 in. w.c. or 0.40 psi 




55.4 in. w.c. or 2 psi 


for One 
Revolution 




















V4 ft 3 


1ft 3 


2 ft 3 


5 ft 3 


wri 8 ' 


1ft 3 


2 ft 3 


5 ft 3 


V4 ft 3 


1ft 3 


2 ft 3 


5 ft 3 


10 


183 


366 


732 


1831 


18") 


' 370 


739 


1849 


205 


409 


818 


2045 


11 


166 


333 


666 


1665 


168 


336 


672 '; 


1681 


186 


372 


744 


1859 


12 


153 


305 


610 


1526 


i54. : ;it 


it 308 


. 616 


1541 


170 


341 


682 


1704 


13 


141 


282 


563 


1408 


142 : 


284 


569*" 


1422 


157 


315 


629 


1573 


14 


131 


262 


523 


1308 


132 ,v 


I. 264 


528 . 


,. 1.1320 ,;; 


146 


292 


584 


1461 


15 


122 


244 


488 


1221 


123 


246 


■"493?" 


1232 


136 


273 


545 


1363 


16 


114 


229 


458 


1144 


116 y 


231 


462 . 


1155 


128 


256 


511 


1278 


17 


108 


215 


431 


1077 


109 :: " 


r 217 


: ' 43S? H 


1087 


120 


241 


481 


1203 


18 


102 


203 


407 


1017 


103 ; 


': 205 


411 


1027 


114 


227 


454 


1136 


19 


96 


193 


385 


964 


•=97 ■■"■ 


!'•■ 195 


389 


. 973 


108 


215 


431 


1076 


20 


92 


183 


366 


915 


92 


185 


370 


924 


102 


205 


409 


1023 


21 


87 


174 


349 


872 


,«88 ,s 


i- .17,6 


. 352», 


880 


97 


195 


390 


974 


22 


83 


166 


333 


832 


84 


168 


336 " 


840 


93 


186 


372 


930 


23 


80 


159 


318 


796 


; J0..J 


„, 161 


322 ..... 


,804 „■ 


89 


178 


356 


889 


24 


76 


153 


305 


763 


*v77' "■'• 


: 154 


308 - 


770 : 


85 


170 


341 


852 


25 


73 


146 


293 


732 


.74 „ 


148 


296 


739 


82 


164 


327 


818 


26 


70 


141 


282 


704 


71 


r fig 


' 284 ! 


711 


79 


157 


315 


787 


27 


68 


136 


271 


678 


68 


137 


274 


,685 


76 


151 


303 


757 


28 


65 


131 


262 


654 


-66 ,:4 


> 132 


264 


660 


73 


146 


292 


730 


29 


63 


126 


253 


631 


■64 '■ 


: 127 


255 f 


'637 ; 


71 


141 


282 


705 


30 


61 


122 


244 


610 


62 


123 


246 


616 


68 


136 


273 


682 


31 


59 


118 


236 


591 


60 :: 


119 


239 


596 


66 


132 


264 


660 


32 


57 


114 


229 


572 


.:58 .... 


116 


231. 


1578 ; 


64 


128 


256 


639 


33 


55 


111 


222 


555 


56 


112 


224 " 


560 " 


62 


124 


248 


620 


34 


54 


108 


215 


539 


; 54 > 


109 


217 


544 i 


60 


120 


241 


602 


35 


52 


105 


209 


523 


53 


: ' 106 


; . 2 11#H 


■528 


58 


117 


234 


584 


36 


51 


102 


203 


509 


51 : 


103 


205 


514 .' 


57 


114 


227 


568 


37 


49 


99 


198 


495 


- :,50 ■,-;. 


;. 100 


200 ;,, 


500 


55 


111 


221 


553 


38 


48 


96 


193 


482 


49 


97 


195" 


?486 ; 


54 


108 


215 


538 


39 


47 


94 


188 


469 


,i.7 .... 


95 


190... 


474 


52 


105 


210 


524 


40 


46 


92 


183 


458 


46 v} 


'" 92 


" 185" 


462 


51 


102 


205 


511 


41 


45 


89 


179 


447 


45 ,. 


90 


180.; 


,451 


50 


100 


200 


499 


42 


44 


87 


174 


436 


u 44 w 


!-• 8B 


- 176' : ?:*: 


440 . 


49 


97 


195 


487 


43 


43 


85 


170 


426 


43 


86 


172. 


430 


48 


95 


190 


476 


44 


42 


83 


166 


416 


42 


84 


• 168 


420 


46 


93 


186 


465 


45 


41 


81 


163 


407 


"41 : 


" 82 


164 


411 


45 


91 


182 


454 


46 


40 


80 


159 


398 


40 


80 


, .161 


402. 


44 


89 


178 


445 


47 


39 


78 


156 


390 


39 ;; 


" : 79 


\br. - 


'393 


44 


87 


174 


435 


48 


38 


76 


153 


381 


,39 ; 


77 


154 


385 


43 


85 


170 


426 


49 


37 


75 


149 


374 


38 


'""'" '75 


151- : 


377' 4 


42 


83 


167 


417 


50 


37 


73 


146 


366 


37 


74 


148 


370 


41 


82 


164 


409 



(continues) 



2006 Edition 



54-118 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-118 



Table A. 1 1 . 1 . 1 Continued 





Size of Test Meter Dial 






Meter Pressure 




■i Bieter Pressure ';'; ;. 




Meter Pressure 




Seconds 


7.0 in. w.c. 


or 0.25 psi 


110 in. w.c. or 0.415 p,i 




55.4 in. w.c. or 2 psi 


for One 
Revolution 










: :■■■■ . «i-5 ' I" ■ ■ .:. ' : \ 










V4 ft 3 


1ft 3 


2 ft* 


5 ft 3 


!* ft 3 


1ft 3 


2 ft 3 


5 ft 3 


>/2 ft 3 


1ft 3 


2 ft 3 


5 ft 3 


51 


36 


72 


144 


359 


36 


72 


145 


;,;362 


40 


80 


160 


401 


52 


35 


70 


141 


352 


36. : . 


71 


142 


356 


39 


79 


157 


393 


53 


35 


69 


138 


345 


35 


•70 


140 


349 


39 


77 


154 


386 


54 


34 


68 


136 


339 


34 


68 


137 


342 


38 


76 


151 


379 


55 


33 


67 


133 


333 


34 


67 ; 


134 


336 


37 


74 


149 


372 


56 


33 


65 


131 


327 


33 


66 


132 


330 


37 


73 


146 


365 


57 


32 


64 


128 


321 


32 


65 


130 


324 


36 


72 


144 


359 


58 


32 


63 


126 


316 


32 


:64 ■ 


127 


,.319 


35 


71 


141 


353 


59 


31 


62 


124 


310 


. 31 


: 63 


125 


313 


35 


69 


139 


347 


60 


31 


61 


122 


305 


„ 31 


62 


123 


1 308 : 


34 


68 


136 


341 


62 


30 


59 


118 


295 


30 


60 


119 


298 


33 


66 


132 


330 


64 


29 


57 


114 


286 


29 


38 


116 


! 289" 


32 


64 


128 


320 


66 


28 


55 


111 


277 


- 28 


56 


112 


280 


31 


62 


124 


310 


68 


27 


54 


108 


269 


27 


•54 


109 


272 


30 


60 


120 


301 


70 


26 


52 


105 


262 


26 


.53 


106 


264 ■ 


29 


58 


117 


292 


72 


25 


51 


102 


254 


26 


" 51 


103 


257 


28 


57 


114 


284 


74 


25 


49 


99 


247 


25 


50 


100 


250. 


28 


55 


111 


276 


76 


24 


48 


96 


241 


24 


49 


97- 


243 


27 


54 


108 


269 


78 


23 


47 


94 


235 


.-..24.;.' 


47 


95 


" 237 : 


26 


52 


105 


262 


80 


23 


46 


92 


229 


23 


.46 .• 


92 


231 • 


26 


51 


102 


256 


82 


22 


45 


89 


223 


■ 23 


'45 ■' 


90 


225' 


25 


50 


100 


249 


84 


22 


44 


87 


218 


22 


• .-,44 ■ 


88 


220 


24 


49 


97 


243 


86 


21 


43 


85 


213 


21 


is ' 


: 86 ' ' 


215 


24 


48 


95 


238 


88 


21 


42 


83 


208 


21 


•.42 


84 . 


210 


23 


46 


93 


232 


90 


20 


41 


81 


203 


21 


41 


82 


.. 205 


23 


45 


91 


227 


94 


19 


39 


78 


195 


:■ 20 


39 


79 


197 


22 


44 


87 


218 


98 


19 


37 


75 


187 


19 ■ 


38 


75 


189 


21 


42 


83 


209 


100 


18 


37 


73 


183 


r: 18 ■'• 


37 


74 


185 


20 


41 


82 


205 


104 


18 


35 


70 


176 


18 


36 


.. 71 


178 


20 


39 


79 


197 


108 


17 


34 


68 


170 


17 


34 


: 68 


171 


19 


38 


76 


189 


112 


16 


33 


65 


163 


17 


33 


66 


165 


18 


37 


73 


183 


116 


16 


32 


63 


158 


16' 


32 


64 


159 


18 


35 


71 


176 


120 


15 


31 


61 


153 


,: 15 ;'; 


31 : 


62 


154 


17 


34 


68 


170 


130 


14 


28 


56 


141 


14 : 


28 


57 


142 


16 


31 


63 


157 


140 


13 


26 


52 


131 


*■ 13 ;: 


i26 


53 


-132- 


15 


29 


58 


146 


150 


12 


24 


49 


122 


12 


25 


49 


123 


14 


27 


55 


136 


160 


11 


23 


46 


114 


■: 12 ' 


23 


413 


' .116: 


13 


26 


51 


128 


170 


11 


22 


43 


108 


11 


„i22 .; 


\ . 43... 


. 109 


12 


24 


48 


120 


180 


10 


20 


41 


102 


■' 10 ' 


; 21 


41 ' 


103 


11 


23 


45 


114 



Note: To convert to Btu per hour, multiply the cubic feet per hour of gas by the Btu per cubic foot heating 
value of the gas used. 



A. 11. 2 Normally, the primary air adjustment should first be set 
to give a soft blue flame having luminous tips and then increased 
to a point where the yellow tips just disappear. If the burner can- 
not be so adjusted, the manufacturer or serving gas supplier 
should be contacted. 

A.11.6 A procedure for checking draft can be found in An- 
nex H, steps 7, 8, and 10 through 14. 

A.12.3.3 Information on the construction and installation 
of ventilating hoods can be obtained from NFPA 96, Stan- 



dard for Ventilation Control and Fire Protection of Commercial 
Cooking Operations. 

A.12.4.4 See A.12.3.3. 

A.12.6.1.3 For information on the installation of gas vents in 
existing masonry chimneys, see Section 12.7. 

A.12.6.5.3 Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVAC Systems and Equipment. 



2006 Edition 



ANSI Z223. 1-119 



ANNEX A 



54-119 



Mechanical 
draft vent 
terminal 
(see 12.9.1) 



Direct-vent terminal clearance 
Minimum clearance, C 
Input (Btu/hr) Clearance (in 

10.000 or less 

10.001 to 50,000 
Over 50,000 
(see 12.9.3) 

For SI units: 1 ft = 0.305 m; 1 in. 
1 Btu/hr = 0.293 W 




Forced air 

inlet 



: 25.4 mm 



FIGURE A.12.9 Exit Terminals of Mechanical Draft and Direct-Vent Venting Systems. 



A. 12.7.3.1 Additional information on sizing venting systems 
can be found in the following: 

(1) Tables in Chapter 13 

(2) The appliance manufacturer's instructions 

(3) The vent system manufacturer's sizing instructions 

(4) Drawings, calculations, and specifications provided by the 
vent system manufacturer 

(5) Drawings, calculations, and specifications provided by a 
competent person 

(6) The chapter on chimney, gas vent, and fireplace systems 
of the ASHRAE Handbook — HVAC Systems and Equipment 

Category I appliances may be either draft hood-equipped 
or a fan-assisted combustion system in design. Different vent 
design methods are required for draft hood-equipped and 
fan-assisted combustion system appliances. 

A.12.8.2 Data on winter design temperature can be found in 
Figure G.2.4 and the 1993 edition of the ASHRAE Handbook — 
Fundamentals. 

A.12.8.5(l) Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVAC Systems and Equipment. 

A.12.9 See Figure A.12.9. 

A.12.11.3 Reference can also be made to the chapter on 
chimney, gas vent, and fireplace systems of the ASHRAE Hand- 
book — HVA C Systems and Equipment. 

A.12.13.4 A device that will automatically shut off gas to the 
burner in the event of sustained backdraft is recommended if 
such backdraft might adversely affect burner operation or if 
flue gas spillage might introduce a hazard. Figure A.12.13.4 



shows examples of correct and incorrect locations for baro- 
metric draft regulators. 

A. 13. 1.7 A long radius turn is a turn where the centerline 
radius is equal to or greater than 1.5 times the vent diameter. 

A.13.2.20 A long radius turn is a turn where the centerline 
radius is equal to or greater than 1.5 times the vent diameter. 




Correct 



& 



Correct 



s 



(a) Correct Locations 



Incorrect -, -. 
( V-O- 



Incorrect 



51 




Incorrect 



r 

X.T3- Incorrect 

"^Incorrect 



]SL 



Incorrect 



(b) Incorrect Locations 
FIGURE A.12.13.4 Locations for Barometric Draft Regulators. 



2006 Edition 



54-120 



NATIONAL, FUEL GAS CODE 



ANSI Z223.1-120 



Annex B Coordination of Appliance and Equipment 
Design, Construction, and Maintenance 

This annex is not apart of the requirements of this NFPA document 
but is included for informational purposes only. 

B.l Coordination. 

B.l.l Because industrial gas applications are so varied in na- 
ture, many agencies are jointly involved with their safe and 
satisfactory use. Prior to installation, the specific assignments 
should be agreed upon by the parties concerned. Atypical, but 
not mandatory, delineation of assignments is given in B.l. 2 
through B.1.5, and a detailed checklist is given in B.2. 

B.1.2 The person or agency planning an installation of appli- 
ances and equipment does the following: 

(1) Verifies the adequacy of the gas supply, volume, pressure, 
and meter location 

(2) Determines suitability of gas for the process 

(3) Notifies gas suppliers of significant changes in requirements 

B.l. 3 Upon request, the gas supplier furnishes the user com- 
plete information on the following: 

(1) Combustion characteristics and physical or chemical prop 
erties such as specific gravity, heating value, pressure, and 
the approximate analysis of the gas 

(2) Conditions under which an adequate supply of gas at suit- 
able pressure can be brought to the site 

(3) Continuity of the gas supply 

B.1.4 The appliance or equipment manufacturer or builder 
provides the following: 

(1) Design and construction of all appliances or equipment 
or assemblies shipped from its plant 

(2) Design and construction of all appliances or equipment 
fabricated, erected, or assembled by the appliances or 
equipment manufacturer or builder in the field 

(3) A statement of the maximum hourly Btu input, type of 
gas, and design pressure range 

(4) Written installation and operating instructions for the user 

B.1.5 The person or agency installing the appliances or 
equipment and the person or agency authorizing the installa- 
tion of appliances or equipment (purchaser) jointly should do 
the following: 

(1) Select, erect, or assemble appliances and equipment, com- 
ponents, or designs purchased or developed by that person 
or agency 

(2) Ensure conformance to codes, ordinances, or regulations 
applicable to the installation 

(3) Provide adequate means of disposal of products of com- 
bustion 

(4) Initially operate the appliances or equipment in a safe 
manner 

B.2 Appliance and Equipment Design and Construction 
Checklist. 

B.2.1 The basic design and installation should consider the 
following: 

(1) Suitability of appliance and equipment for process re- 
quirements 

(2) Adequate structural strength and stability 

(3) Reasonable life expectancy 

(4) Conformance to existing safety standards 



(5) Adequate combustion space and venting 

(6) Means for observation and inspection of combustion 

B.2. 2 Materials of construction used, other than pipe, fit- 
tings, and valves, should provide reasonable life expectancy 
for the service intended and should be capable of satisfactorily 
withstanding the following: 

(1) Operating temperatures 

(2) Chemical action 

(3) Thermal shock 

(4) Load stresses 

B.2. 3 Combustion systems should be selected for the charac- 
teristics of the available gas so that they will operate properly at 
the elevation at point of use and produce the following: 

( 1 ) Proper heat distribution 

(2) Adequate operating temperature range 

(3) Suitable flame geometry 

(4) Flame stability 

(5) Operating flexibility 

(6) Desired heating chamber atmosphere 

B.2.4 Pipe, fittings, and valves should conform to applicable 
American National Standards as indicated in Section 5.6. Pip- 
ing, bushings, and material in fittings should not be selected 
or used until the following factors have been considered: 

(1) Correct size to handle required volume (consideration of 
pressure drop in controls and manifolds is particularly 
important in low-pressure systems) 

(2) Material specifications suitable for pressures and tem- 
peratures encountered 

(3) Adequate supports and protection against physical damage 

(4) Tight assembly and thorough leak inspection 

(5) Use of sufficient unions and flanges, where permitted, for 
convenient field replacement or repair 

(6) Arrangement of piping to provide accessibility for appliance 
and equipment adjustments and freedom from thermal 
damage 

B.2.5 Information concerning the characteristics of the gas 
and electricity available at the point of utilization should be 
specific and complete. Gas controls and electrical systems 
should be selected to conform to these characteristics, which 
include the following: 

(1) Gas characteristics: Heat content, pressure, specific grav- 
ity, and approximate analysis 

(2) Electrical characteristics: Voltages, number of phases, and 
frequencies for both control and power circuits 

(3) Location of electrical equipment and wiring to avoid ther- 
mal damage and excessive concentrations of dust, dirt, or 
foreign material 

(4) Requirements of applicable electrical codes and standards, 
with particular reference to NFPA 70, National Electrical Code 

B.2. 6 Temperature controls, if used, should be selected, with 
consideration of the following: 

(1) Range and type of instruments and sensing elements 

(2) Type of control action 

(3) Suitability for service required 

(4) Correlation of control instruments with operating equip- 
ment 

B.2. 7 In enclosed chambers, the accumulation of gas-air or 
solvent-air mixtures that can be accidentally ignited consti- 
tutes a potential hazard to life and property. For this reason, 
consideration should be given to the selection and installation 



2006 Edition 



ANSIZ223.1-121 



ANNEX C 



54-121 



of suitable protective equipment. The selection of a satisfac- 
tory protective system and components not otherwise covered 
by existing codes or standards should be based on the require- 
ments of each individual installation after consultation with 
the various interested parties, including the user, designer, 
insurance company, and local authorities having jurisdiction. 
Factors and considerations involved in the selection of protec- 
tive equipment include the following: 

(1) Feasibility of its installation 

(2) Its adaptability to process and control requirements 

(3) Conformance to existing standards, ordinances, require- 
ments, and other regulations that apply (See Annex L for the 
listing of standards and specifications.) 

B.3 Maintenance of Appliances and Equipment. 

B.3.1 These recommendations are prepared for mainte- 
nance of appliances and equipment. Special types of appli- 
ances and equipment demand special attention. 

B.3.2 Burners and pilots should be kept clean and in proper 
operating condition. Burner refractory parts should be exam- 
ined at frequent regular intervals to ensure good condition. 

B.3. 3 Where automatic flame safeguards are used, a com- 
plete shutdown and restart should be made at frequent inter- 
vals to check the components for proper operation. 

B.3.4 Other Safeguard Equipment. 

B.3.4.1 Accessory safeguard equipment, such as manual reset 
valves with pressure or vacuum switches, high-temperature 
limit switches, draft controls, shutoff valves, airflow switches, 
door switches, and gas valves, should be operated at frequent 
regular intervals to ensure proper functioning. If inoperative, 
they should be repaired or replaced promptly. 

B.3.4.2 Where firechecks are installed in gas-air mixture pip- 
ing to prevent flashbacks from traveling farther upstream, the 
pressure loss across the firechecks sbould be measured at 
regular intervals. When excessive pressure loss is found, 
screens should be removed and cleaned. Water-type backfire 
checks should be inspected at frequent regular intervals and 
liquid level maintained. 

B. 3.4.3 All safety shutoff valves should be checked for leakage 
and proper operation at frequent regular intervals. 

B.3.5 Auxiliary Devices. 

B.3.5.1 Anecessary part of the appliance or equipment main- 
tenance is the proper maintenance of auxiliary devices. Main- 
tenance instructions as supplied by the manufacturers of these 
devices should be followed. 

B.3. 5.2 Gas combustion systems, including blowers, mechani- 
cal mixers, control valves, temperature control instruments, 
air valves, and air filters, should be kept clean and should be 
examined at frequent regular intervals. 

B.3.5.3 Necessary repairs and replacements should be made 
promptly. 

B.3.6 Regulator and zero governor vents and impulse or con- 
trol piping and tubing should be kept clear. Regulator valves 
that operate improperly should be cleaned, repaired, or re- 
placed promptly. 

B.3.7 A necessary part of the appliance or equipment main- 
tenance is the proper maintenance of the gas piping system. It 
is recommended that gas piping be inspected and tested for 



leakage at regular intervals in accordance with the provisions 
of 8.1.5. Air piping should be kept internally clean to prevent 
accumulation of dust, lint, and grease in air jets and valves. 
Where conditions warrant, filters should be installed at the 
intake to the fans. 

B.3.8 Standby or substitute fuel equipment and systems for 
appliances or equipment should be kept in good operating 
condition and tested periodically. 

B.3.9 An adequate supply of repair parts should be maintained. 



Annex C Sizing and Capacities of Gas Piping 

This annex is not apart of the requirements of this NFPA document 
but is included for informational purposes only. 

C.l Sizing Factors. The first goal of determining the pipe sizing 
of a fuel gas piping system is to be assured that there is sufficient 
gas pressure at the inlet to each appliance. The majority of sys- 
tems are residential, and the appliances will all have the same, or 
nearly the same, requirement for minimum gas pressure at the 
appliance inlet. This pressure will be about 5 in. w.c, which is 
enough for proper operation of the appliance regulator to de- 
liver about 3.5 in. to the burner itself. The pressure drop in the 
piping is subtracted from the source delivery pressure to verify 
that the minimum is available at the appliance. 

There are other systems, however, where the required inlet 
pressure to the different appliances may be quite varied. In 
such cases, the greatest inlet pressure required must be satis- 
fied, as well as the farthest appliance, which is almost always 
the critical appliance in small systems. 

There is an additional requirement to be observed besides 
the capacity of the system at 100 percent flow. That require- 
ment is that at minimum flow, the pressure at the inlet to any 
appliance does not exceed the pressure rating of the appli- 
ance regulator. This would seldom be of concern in small sys- 
tems if the source pressure is 14 psi (14 in. w.c.) (3.4 kPa) or 
less, but it should be verified for systems with greater gas pres- 
sure at the point of supply. 

C.2 General Pipe Sizing Considerations. To determine the 
size of piping used in a gas piping system, the following factors 
must be considered: 

( 1 ) Allowable loss in pressure from point of delivery to appliance 

(2) Maximum gas demand 

(3) Length of piping and number of fittings 

(4) Specific gravity of the gas 

(5) Diversity factor 

For any gas piping system, or special appliance, or for con- 
ditions other than those covered by the tables provided in this 
code, such as longer runs, greater gas demands, or greater 
pressure drops, the size of each gas piping system should be 
determined by standard engineering practices acceptable to 
the authority havingjurisdiction. 

C.3 Description of Tables. 

C.3.1 General. The quantity of gas to be provided at each 
outlet should be determined, whenever possible, direcdy from 
the manufacturer's gas input Btu/hr rating of the appliance 
that will be installed. In case the ratings of the appliances to be 
installed are not known, Table 5.4.2.1 shows the approximate 
consumption (in Btu per hour) of certain types of typical 
household appliances. 



2006 Edition 



54-122 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-122 



To obtain the cubic feet per hour of gas required, divide 
the total Btu/hr input of all appliances by the average Btu 
heating value per cubic foot of the gas. The average Btu per 
cubic foot of the gas in the area of the installation can be 
obtained from the serving gas supplier. 

C.3.2 Low Pressure Natural Gas Tables. Capacities for gas at low 

pressure [2.0 psig (14 kPa gauge) or less] in cubic feet per hour 
of 0.60 specific gravity gas for different sizes and lengths are 
shown in Table 6.2(a) and Table 6.2(b) for iron pipe or equiva- 
lent rigid pipe, in Table 6.2(f) through Table 6.2(h) for smooth 
wall semi-rigid tubing, and in Table 6.2(m) and Table 6.2(o) for 
corrugated stainless steel tubing. Table 6.2(a) and Table 6.2(f) 
are based on a pressure drop of 0.3 in. w.c. (75 Pa), whereas 



Table 6.2(b) , Table 6.2 (g) , and Table 6.2 (m) are based on a pres- 
sure drop of 0.5 in. w.c. (125 Pa). Table 6.2(h), Table 6.2(n), and 
Table 6.2 (o) are special low-pressure applications based on pres- 
sure drops greater than 0.5 in. w.c. (125 Pa). In using 
Table 6.2(h), Table 6.2 (n), or Table 6.2 (o), an allowance (in 
equivalent length of pipe) should be considered for any piping 
run with four or more fittings (see Table C.3.2). 

C.3.3 Undiluted Liquefied Petroleum Gas Tables. Capacities 
in thousands of Btu per hour of undiluted liquefied petroleum 
gases based on a pressure drop of 0.5 in. w.c. (125 Pa) for differ- 
ent sizes and lengths are shown in Table 6.3(d) for iron pipe or 
equivalent rigid pipe, in Table 6.3(f) for smooth wall semi-rigid 
tubing, in Table 6.3(h) for corrugated stainless steel tubing, and 



Table C.3.2 Equivalent Lengths of Pipe Fittings and Valves 














Screwed Fittings 1 


90° Welding Elbows and Smooth Bends 2 




45°/Ell 


90VFJ1 


180° 

Close 

Return 

Bends 


Tee 


R/d=\ 


R/d- 


R/d=2 


R/d=4 


R/d=6 


R/d=8 




k factor = 


0.42 


0.90 


2.00 


1.80 


0.48 


0.36 


0.27 


0.21 


0.27 


0.36 


L/cTratio 4 n = 


14 


30 


67 


60 


16 


12 


9 


7 


9 


12 


Nominal 
Pipe 
Size 

(in.) 


Inside 

Diam. d (in.), 

Sched. 40 6 


^ 


# 


^ 


A 


^ 


^ 











L = Equivalent Length in Feet of Schedule 40 (Standard Weight) Straight Pipe 6 



Vi 


0.622 


0.73 


1.55 


3.47 


3.10 


0.83 


0.62 


0.47 


0.36 


0.47 


0.62 


y 4 


0.824 


0.96 


2.06 


4.60 


4.12 


1.10 


0.82 


0.62 


0.48 


0.62 


0.82 


l 


1.049 


1.22 


2.62 


5.82 


5.24 


1.40 


1.05 


0.79 


0.61 


0.79 


1.05 


1V4 


1.380 


1.61 


3.45 


7.66 


6.90 


1.84 


1.38 


1.03 


0.81 


1.03 


1.38 


V/2 


1.610 


1.88 


4.02 


8.95 


8.04 


2.14 


1.61 


1.21 


0.94 


1.21 


1.61 


2 


2.067 


2.41 


5.17 


11.5 


10.3 


2.76 


2.07 


1.55 


1.21 


1.55 


2.07 


2 l A 


2.469 


2.88 


6.16 


13.7 


12.3 


3.29 


2.47 


1.85 


1.44 


1.85 


2.47 


3 


3.068 


3.58 


7.67 


17.1 


15.3 


4.09 


3.07 


2.30 


1.79 


2.30 


3.07 


4 


4.026 


4.70 


10.1 


22.4 


20.2 


5.37 


4.03 


3.02 


2.35 


3.02 


4.03 


5 


5.047 


5.88 


12.6 


28.0 


25.2 


6.72 


5.05 


3.78 


2.94 


3.78 


5.05 


6 


6.065 


7.07 


15.2 


33.8 


30.4 


8.09 


6.07 


4.55 


3.54 


4.55 


6.07 


8 


7.981 


9.31 


20.0 


44.6 


40.0 


10.6 


7.98 


5.98 


4.65 


5.98 


7.98 


10 


10.02 


11.7 


25.0 


55.7 


50.0 


13.3 


10.0 


7.51 


5.85 


7.51 


10.0 


12 


11.94 


13.9 


29.8 


66.3 


59.6 


15.9 


11.9 


8.95 


6.96 


8.95 


11.9 


14 


13.13 


15.3 


32.8 


73.0 


65.6 


17.5 


13.1 


9.85 


7.65 


9.85 


13.1 


16 


15.00 


17.5 


37.5 


83.5 


75.0 


20.0 


15.0 


11.2 


8.75 


11.2 


15.0 


18 


16.88 


19.7 


42.1 


93.8 


84.2 


22.5 


16.9 


12.7 


9.85 


12.7 


16.9 


20 


18.81 


22.0 


47.0 


105 


94.0 


25.1 


18.8 


14.1 


11.0 


14.1 


18.8 


24 


22.63 


26.4 


56.6 


126 


113 


30.2 


22.6 


17.0 


13.2 


17.0 


22.6 



2006 Edition 



ANSIZ223.1-123 



ANNEX C 



54-123 



in Table 6.3(k) and Table 6.3(m) for polyethylene plastic pipe 
and tubing. Table 6.3(i) and Table 6.3 (j) for corrugated stainless 
steel tubing and Table 6.3(1) for polyethylene plastic pipe are 
based on operating pressures greater than 0.5 psi (3.5 kPa) and 
pressure drops greater than 0.5 in. w.c. (125 Pa). In using these 
tables, an allowance (in equivalent length of pipe) should be con- 
sidered for any piping run with four or more fittings (see Table 
C.3.2). 

C.3.4 Natural Gas Specific Gravity. Gas piping systems that 
are to be supplied with gas of a specific gravity of 0.70 or less 
can be sized directly from the tables provided in this code, 
unless the authority having jurisdiction specifies that a gravity 
factor be applied. Where the specific gravity of the gas is 
greater than 0.70, the gravity factor should be applied. 



Application of the gravity factor converts the figures given 
in the tables provided in this code to capacities for another gas 
of different specific gravity. Such application is accomplished 
by multiplying the capacities given in the tables by the multi- 
pliers shown in Table C.3.4. In case the exact specific gravity 
does not appear in the table, choose the next higher value 
specific gravity shown. 

C.3.5 Higher Pressure Natural Gas Tables. Capacities for gas 
at pressures of 2 psi and greater in cubic feet per hour of 0.60 
specific gravity gas for different sizes and lengths are shown in 
Table 6.2(c) and Table 6.2(d) for iron pipe or equivalent rigid 
pipe, Table 6.2(j) through Table 6.2(1) for semi-rigid tubing, 
Table 6.2(p) and Table 6.2(q) for corrugated stainless steel 
tubing, and Table 6.2 (s) and Table 6.2 (t) for polyethylene 
plastic pipe. 



Table C.3.2 Continued 



Miter Elbows 3 (No. of Miters) 



Welding Tees 



Valves (Screwed, Flanged, or Welded) 



1-45° 



1-60° 



1-90° 



2-90° 



3-90° 



Forged 



Miter 



Gate 



Globe 



Angle 



Swing 
Check 



0.45 



0.90 



1.80 



0.60 



0.45 



1.35 



1.80 



0.21 



10 



5.0 



2.5 



15 



30 



60 



20 



15 



45 



60 



333 



167 



83 



n> 



%> 



^ 



^ 



^ 



& 



a 







L = Equivalent Length in Feet of Schedule 40 (Standard Weight) Strai 


ight Pipe 6 






0.78 


1.55 


3.10 


1.04 


0.78 


2.33 


3.10 


0.36 


17.3 


8.65 


4.32 


1.03 


2.06 


4.12 


1.37 


1.03 


3.09 


4.12 


0.48 


22.9 


11.4 


5.72 


1.31 


2.62 


5.24 


1.75 


1.31 


3.93 


5.24 


0.61 


29.1 


14.6 


7.27 


1.72 


3.45 


6.90 


2.30 


1.72 


5.17 


6.90 


0.81 


38.3 


19.1 


9.58 


2.01 


4.02 


8.04 


2.68 


2.01 


6.04 


8.04 


0.94 


44.7 


22.4 


11.2 


2.58 


5.17 


10.3 


3.45 


2.58 


7.75 


10.3 


1.21 


57.4 


28.7 


14.4 


3.08 


6.16 


12.3 


4.11 


3.08 


9.25 


12.3 


1.44 


68.5 


34.3 


17.1 


3.84 


7.67 


15.3 


5.11 


3.84 


11.5 


15.3 


1.79 


85.2 


42.6 


21.3 


5.04 


10.1 


20.2 


6.71 


5.04 


15.1 


20.2 


2.35 


112 


56.0 


28.0 


6.30 


12.6 


25.2 


8.40 


6.30 


18.9 


25.2 


2.94 


140 


70.0 


35.0 


7.58 


15.2 


30.4 


10.1 


7.58 


22.8 


30.4 


3.54 


168 


84.1 


42.1 


9.97 


20.0 


40.0 


13.3 


9.97 


29.9 


40.0 


4.65 


222 


111 


55.5 


12.5 


25.0 


50.0 


16.7 


12.5 


37.6 


50.0 


5.85 


278 


139 


69.5 


14.9 


29.8 


59.6 


19.9 


14.9 


44.8 


59.6 


6.96 


332 


166 


83.0 


16.4 


32.8 


65.6 


21.9 


16.4 


49.2 


65.6 


7.65 


364 


182 


91.0 


18.8 


37.5 


75.0 


25.0 


18.8 


56.2 


75.0 


8.75 


417 


208 


104 


21.1 


42.1 


84.2 


28.1 


21.1 


63.2 


84.2 


9.85 


469 


234 


117 


23.5 


47.0 


94.0 


31.4 


23.5 


70.6 


94.0 


11.0 


522 


261 


131 


28.3 


56.6 


113 


37.8 


28.3 


85.0 


113 


13.2 


629 


314 


157 



For SI units, 1 ft = 0.305 m. 

Note: Values for welded Fittings are for conditions where bore is not obstructed by weld spatter or backing rings. If 

appreciably obstructed, use values for "Screwed Fittings." 

'Flanged fittings have three-fourths the resistance of screwed elbows and tees. 

2 Tabular figures give the extra resistance due to curvature alone to which should be added the full length of travel. 

3 Small size socket-welding fittings are equivalent to miter elbows and miter tees. 

""Equivalent resistance in number of diameters of straight pipe computed for a value of/- 0.0075 from the relation n - 

5 For condition of minimum resistance where the centerline length of each miter is between dand 2'/2<£ 

6 For pipe having other inside diameters, the equivalent resistance may be computed from the above n values. 

Source: From Piping Handbook, Table XIV, pp. 100-101. Used by permission of McGraw-Hill Book Company. 



A/4/ 



2006 Edition 



54-124 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-124 



Table C.3.4 SPECIAL USE: Multipliers to Be 
Used with Tables 6.2(a) Through 6.2(v) When the 
Specific Gravity of the Gas Is Other Than 0.60 



Specific 
Gravity 


Multiplier 


Specific 
Gravity 


Multiplier 


0.35 
0.40 
0.45 


1.31 
1.23 
1.16 


1.00 
1.10 
1.20 


0.78 
0.74 
0.71 


0.50 
0.55 
0.60 


1.10 
1.04 
1.00 


1.30 
1.40 
1.50 


0.68 
0.66 
0.63 


0.65 
0.70 
0.75 


0.96 
0.93 

0.90 


1.60 
1.70 
1.80 


0.61 
0.59 
0.58 


0.80 
0.85 
0.90 


0.87 
0.84 
0.82 


1.90 
2.00 
2.10 


0.56 
0.55 

0.54 



C.4 Use of Capacity Tables. 

C.4. 1 The Longest Length Method. This sizing method is con- 
servative in its approach by applying the maximum operating 
conditions in the system as the norm for the system and by 
setting the length of pipe used to size any given part of the 
piping system to the maximum value. 

To determine the size of each section of gas piping in a 
system within the range of the capacity tables, proceed as fol- 
lows. (Also see sample calculations included in this annex.) 

(1) Divide the piping system into appropriate segments con- 
sistent with the presence of tees, branch lines, and main 
runs. For each segment, determine the gas load (assum- 
ing all appliances operate simultaneously) and its overall 
length. An allowance (in equivalent length of pipe) as 
determined from Table C.3.2 shall be considered for pip- 
ing segments that include four or more fittings. 

(2) Determine the gas demand of each appliance to be at- 
tached to the piping system. Where Table 6.2(a) through 
Table 6.2 (v) are to be used to select the piping size, calcu- 
late the gas demand in terms of cubic feet per hour for 
each piping system outlet. Where Table 6.3(a) through 
Table 6.3 (m) are to be used to select the piping size, cal- 
culate the gas demand in terms of thousands of Btu per 
hour for each piping system outlet. 

(3) Where the piping system is for use with other than undiluted 
liquefied petroleum gases, determine the design system 
pressure, the allowable loss in pressure (pressure drop), and 
specific gravity of the gas to be used in the piping system. 

(4) Determine the length of piping from the point of delivery 
to the most remote outiet in the building/piping system. 

(5) In the appropriate capacity table, select the row showing 
the measured length or the next longer length if the table 
does not give the exact length. This is the only length used 
in determining the size of any section of gas piping. If the 
gravity factor is to be applied, the values in the selected 
row of the table are multiplied by the appropriate multi- 
plier from Table C.3.4. 

(6) Use this horizontal row to locate ALL gas demand figures 
for this particular system of piping. 

(7) Starting at the most remote outlet, find the gas demand 
for that outlet in the horizontal row just selected. If the 
exact figure of demand is not shown, choose the next 
larger figure left in the row. 



(8) Opposite this demand figure, in the first row at the top, 
the correct size of gas piping will be found. 

(9) Proceed in a similar manner for each outlet and each 
section of gas piping. For each section of piping, deter- 
mine the total gas demand supplied by that section. 

When a large number of piping components (such as elbows, 
tees, and valves) are installed in a pipe run, additional pressure 
loss can be accounted for by the use of equivalent lengths. Pres- 
sure loss across any piping component can be equated to the 
pressure drop through a length of pipe. The equivalent length of 
a combination of only four elbows/ tees can result in a jump to 
the next larger length row, resulting in a significant reduction in 
capacity. The equivalent lengths in feet shown in Table C.3.2 have 
been computed on a basis that the inside diameter corresponds 
to that of Schedule 40 (standard-weight) steel pipe, which is close 
enough for most purposes involving other schedules of pipe. 
Where a more specific solution for equivalent length is desired, 
this may be made by multiplying the actual inside diameter of the 
pipe in inches by n/12, or the actual inside diameter in feet by n. 
N can be read from the table heading. The equivalent length 
values can be used with reasonable accuracy for copper or brass 
fittings and bends, although the resistance per foot of copper or 
brass pipe is less than that of steel. For copper or brass valves, 
however, the equivalent length of pipe should be taken as 45 per- 
cent longer than the values in the table, which are for steel pipe. 

C.4.2 The Branch Length Method. This sizing method re- 
duces the amount of conservatism built into the traditional 
Longest Length Method. The longest length as measured 
from the meter to the farthest remote appliance is used only to 
size the initial parts of the overall piping system. The Branch 
Length Method is applied in the following manner: 

(1) Determine the gas load for each of the connected appli- 
ances. 

(2) Starting from the meter, divide the piping system into 
a number of connected segments, and determine the 
length and amount of gas that each segment would 
carry assuming that all appliances were operated simul- 
taneously. An allowance (in equivalent length of pipe) 
as determined from Table C.3.2 should be considered 
for piping segments that include four or more Fittings. 

(3) Determine the distance from the outlet of the gas meter 
to the appliance farthest removed from the meter. 

(4) Using the longest distance (found in Step 3), size each 
piping segment from the meter to the most remote appli- 
ance oudet. 

(5) For each of these piping segments, use the longest length 
and the calculated gas load for all of the connected appli- 
ances for the segment and begin the sizing process in Steps 6 
through 8. 

(6) Referring to the appropriate sizing table (based on oper- 
ating conditions and piping material), find the longest 
length distance in the first column or the next larger dis- 
tance if the exact distance is not listed. The use of alterna- 
tive operating pressures and/or pressure drops will re- 
quire the use of a different sizing table but will not alter 
the sizing methodology. In many cases, the use of alterna- 
tive operating pressures and/ or pressure drops will re- 
quire the approval of both the authority having jurisdic- 
tion and the local gas serving utility. 

(7) Trace across this row until the gas load is found or the 
closest larger capacity if the exact capacity is not listed. 

(8) Read up the table column and select the appropriate pipe 
size in the top row. Repeat Steps 6, 7, and 8 for each pipe 
segment in the longest run. 



2006 Edition 



ANSIZ223.1-125 



ANNEX C 



54-125 



(9) Size each remaining section of branch piping not previ- 
ously sized by measuring the distance from the gas meter 
location to the most remote oudet in that branch, using 
the gas load of attached appliances and follow the proce- 
dures of Steps 2 through 8. 

C.4.3 Hybrid Pressure Method. The sizing of a 2 psi (14 kPa) 
gas piping system is performed using the traditional Longest 
Length Method but with modifications. The 2 psi (14 kPa) 
system consists of two independent pressure zones, and each 
zone is sized separately. The Hybrid Pressure Method is ap- 
plied as follows. 

The 2 psi (14 kPa) section (from the meter to the line regula- 
tor) is sized as follows: 

(1) Calculate the gas load (by adding up the name plate rat- 
ings) from all connected appliances. (In certain circum- 
stances the installed gas load may be increased up to 
50 percent to accommodate future addition of appli- 
ances.) Ensure that the line regulator capacity is adequate 
for the calculated gas load and that the required pressure 
drop (across the regulator) for that capacity does not ex- 
ceed S A psi (5.2 kPa) for a 2 psi (14 kPa) system. If the 
pressure drop across the regulator is too high (for the 
connected gas load), select a larger regulator. 

(2) Measure the distance from the meter to the line regulator 
located inside the building. 

(3) If there are multiple line regulators, measure the distance 
from the meter to the regulator farthest removed from 
the meter. 

(4) The maximum allowable pressure drop for the 2 psi 
(14 kPa) section is 1 psi (7 kPa). 

(5) Referring to the appropriate sizing table (based on piping 
material) for 2 psi (14 kPa) systems with a 1 psi (7 kPa) pres- 
sure drop, find this distance in the first column, or the clos- 
est larger distance if the exact distance is not listed. 

(6) Trace across this row until the gas load is found or the 
closest larger capacity if the exact capacity is not listed. 

(7) Read up the table column to the top row and select the 
appropriate pipe size. 

(8) If there are multiple regulators in this portion of the piping 
system, each line segment must be sized for its actual gas 
load, but using the longest length previously determined. 

The low-pressure section (all piping downstream of the 
line regulator) is sized as follows: 

(1) Determine the gas load for each of the connected appli- 
ances. 

(2) Starting from the line regulator, divide the piping system 
into a number of connected segments and/or independent 
parallel piping segments and determine the amount of gas 
that each segment would carry assuming that all appliances 
were operated simultaneously. An allowance (in equivalent 
length of pipe) as determined from Table C.3.2 should be 
considered for piping segments that include four or more 
fittings. 

(3) For each piping segment, use the actual length or longest 
length (if there are sub-branch lines) and the calculated gas 
load for that segment and begin the sizing process as follows: 
(a) Referring to the appropriate sizing table (based on 

operating pressure and piping material), find the 
longest length distance in the first column or the clos- 
est larger distance if the exact distance is not listed. 
The use of alternative operating pressures and/or 
pressure drops will require the use of a different siz- 
ing table but will not alter the sizing methodology. In 
many cases, the use of alternative operating pressures 



and/or pressure drops may require the approval of 
the authority havingjurisdiction. 

(b) Trace across this row until the appliance gas load is 
found or the closest larger capacity if the exact capac- 
ity is not listed. 

(c) Read up the table column to the top row and select 
the appropriate pipe size. 

(d) Repeat this process for each segment of the piping 
system. 

C.4.4 Pressure Drop per 100 ft Method. This sizing method is 
less conservative than the others, but it allows the designer to 
immediately see where the largest pressure drop occurs in the 
system. With this information, modifications can be made to 
bring the total drop to the critical appliance within the limita- 
tions that are presented to the designer. 

Follow the procedures described in the Longest Length 
Method for steps (1) through (4) and step (9). 

For each piping segment, calculate the pressure drop 
based on pipe size, length as a percentage of 100 ft, and gas 
flow. Table C.4.4 shows pressure drop per 100 ft for pipe sizes 
from V2 in. through 2 in. The sum of pressure drops to the 
critical appliance is subtracted from the supply pressure to 
verify that sufficient pressure will be available. If not, the lay- 
out can be examined to find the high drop section (s), and 
sizing selections modified. 

C.5 Use of Sizing Equations. Capacities of smooth wall pipe or 
tubing can also be determined by using the following formulas: 

(1) High Pressure [1.5 psi (10.3 kPa) and above]: 



Q = 181.6. 



= 2237D 2 



D>(P*-P 2 2 )Y 
Cr ■ jba ■ L 

CrL 



(2) Low Pressure [less than 1.5 psi (10.3 kPa)]: 



Q = 187.3. 



D b AH 

Cr ■ jba ■ L 



= 2313Z> 2 



AH 
CrL 



where: 
Q = rate, cubic feet per hour at 60°F and 30 in. 

mercury column 
D = inside diameter of pipe, in. 
Pi = upstream pressure, psia 
P 2 = downstream pressure, psia 
Y = superexpansibility factor = 
1/supercompressibility factor 
jba = base friction factor for air at 60°F (CF = 1) 
L = length of pipe, ft 
H = pressure drop, in. w.c. (27.7 in. H 2 = 1 psi) = 

0.00354 ST(Z/S) 0152 
Cr = factor for viscosity, density, and temperature 
S = specific gravity of gas at 60°F and 30 in. mercury 
column (0.60 for natural gas, 1.53 for propane) 
T = absolute temperature, °F or = t + 460 
t = temperature, °F 

Z = viscosity of gas, centipoise (0.012 for natural gas, 
0.008 for propane), or = 1488 

See Table 6.4.2 for values of Cr and Kfor natural gas and 
propane. 



2006 Edition 



54-126 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-126 



Table C.4.4 Thousands of Btu/hr of Natural Gas per 100 ft of Pipe at Various 
Pressure Drops and Pipe Diameters 

d /mn r Pipe Sizes (in.) 



(in. w.c.) 


M> 


3 /4 


1 


VA 


V/2 


2 


0.2 


31 


64 


121 


248 


372 


716 


0.3 


38 


79 


148 


304 


455 


877 


0.5 


50 


104 


195 


400 


600 


1160 


1.0 


71 


147 


276 


566 


848 


1640 



Note: Other values can be obtained using the following equation: 



Desired Value = thousands of Btu/hr x 



Desired Drop 
Table Drop 



For example, if it is desired to get flow through % in. pipe at 2 in. w.c/100 ft, multiply the capacity of % in. pipe at 1 in./lOO ft by the square root 
of the pressure ratio: 



147,000 Btu/hr x J = 147,000x1.414 = 208,000 Btu/hr 

1 in. w.c. 



C.6 Pipe and Tube Diameters. Where the internal diameter is 
determined by the formulas in Section 6.4, Table C.6 (a) and 
Table C.6(b) can be used to select the nominal or standard 
pipe size based on the calculated internal diameter. 

Table C.6(a) Schedule 40 Steel Pipe 
Standard Sizes 



Nominal 


Internal 


Nominal 


Internal 


Size 


Diameter 


Size 


Diameter 


(in.) 


(in.) 


(in.) 


(in.) 


Vi 


0.364 


V/2 


1.610 


% 


0.493 


2 


2.067 


Vi 


0.622 


2M- 


2.469 


% 


0.824 


3 


3.068 


1 


1.049 


y/2 


3.548 


VA 


1.380 


4 


4.026 



C.7 Use of Sizing Charts. A third method of sizing gas piping 
is detailed here as a useful option when large quantities of 
piping are involved in a job (e.g., an apartment house) and 
material costs are of concern. If the user is not completely 
familiar with this method, the resulting pipe sizing should be 
checked by a knowledgeable gas engineer. The sizing charts 
are applied as follows: 

(1) With the layout developed according to Section 5.1 of the 
code, indicate in each section the design gas flow under 
maximum operation conditions. For many layouts, the 
maximum design flow will be the sum of all connected 
loads. However, in some cases, certain combinations of 
appliances will not occur simultaneously (e.g., gas heating 
and air conditioning). For these cases, the design flow is 
the greatest gas flow that can occur at any one time. 

(2) Determine the inlet gas pressure for the system being de- 
signed. In most cases, the point of inlet will be the gas meter 
or service regulator, but in the case of a system addition, it 
could be the point of connection to the existing system. 



Table C.6(b) 


Copper 


Tube Standard Sizes 




Nominal 






Nominal 






or 


Internal 




or 


Internal 


Tube 


Standard 


Diameter 


Tube 


Standard 


Diameter 


Type 


Size (in.) 


(in.) 


Type 


Size (in.) 


(in.) 


K 


>/4 


0.305 


K 


1 


0.995 


L 


1/4 


0.315 


L 


1 


1.025 


ACR (D) 


% 


0.315 


ACR 

(DA) 


l ] /8 


1.025 


ACR (A) 


% 


0.311 


K 


VA 


1.245 


K 


% 


0.402 


L 


VA 


1.265 


L 


% 


0.430 


ACR 

(DA) 


1% 


1.265 


ACR (D) 


Vi 


0.430 


K 


V/2 


1.481 


ACR (A) 


M> 


0.436 


L 


VA 


1.505 


K 


M> 


0.527 


ACR 

(D,A) 


1% 


1.505 


L 


V2 


0.545 


K 


2 


1.959 


ACR (D) 


¥s 


0.545 


L 


2 


1.985 


ACR (A) 


Vs 


0.555 


ACR 

(D,A) 


2Ms 


1.985 


K 


% 


0.652 


K 


2M> 


2.435 


L 


% 


0.666 


L 


VA 


2.465 


ACR (D) 


% 


0.666 


ACR 
(D,A) 


2% 


2.465 


ACR (A) 


% 


0.680 


K 


3 


2.907 


K 


% 


0.745 


L 


3 


2.945 


L 


Y* 


0.785 


ACR 

(D,A) 


3 Ms 


2.945 


ACR 


Vs 


0.785 








(D,A) 













2006 Edition 



ANSIZ223.1-127 



ANNEX C 



54-127 



(3) Determine the minimum pressure required at the inlet to 
the critical appliance. Usually, the critical item will be the 
appliance with the highest required pressure for satisfac- 
tory operation. If several items have the same required 
pressure, it will be the one with the greatest length of 
piping from the system inlet. 

(4) The difference between the inlet pressure and critical item 
pressure is the allowable system pressure drop. Figure C.7(a) and 
Figure C.7(b) show the relationship between gas flow, pipe 
size, and pipe length for natural gas with 0.60 specific gravity. 

(5) To use Figure C.7(a) (low-pressure applications), calculate 
the piping length from the inlet to the critical appliance. 
Increase this length by 50 percent to allow for fittings. Divide 
the allowable pressure drop by the equivalent length (in 
hundreds of feet) to determine the allowable pressure drop 
per hundred feet. Select the pipe size from Figure C.7(a) for 
the required volume of flow. 

(6) To use Figure C.7(b) (high-pressure applications), calculate 
the equivalent length as in item (5). Calculate the index num- 
berfor Figure C.7(b) by dividing the difference between the 
squares of the absolute values of inlet and outlet pressures by 
the equivalent length (in hundreds of feet). Select the pipe 
size from Figure C.7(b) for the gas volume required. 

C.8 Examples of Piping System Design and Sizing. 

C.8.1 Example 1 — Longest Length Method. Determine the 
required pipe size of each section and outlet of the piping 
system shown in Figure C.8.1, with a designated pressure drop 
of 0.50 in. w.c. (125 Pa), using the Longest Length Method. 



The gas to be used has 0.60 specific gravity and a heating value 
ofl000Btu/ft s (37.5 MJ/m 3 ). 

Solution 

( 1 ) Maximum gas demand for outlet A: 



„ ... /rating plate input, or 

Consumption ( Tabl |£ A2J ifnecessary 



Btu of gas 

= 35,000 Btu/hr rating =3535cfh 
1,000 Btu/ft 

Maximum gas demand for outlet B: 

Consumption _ 75,000 _ 7 „ 
Btu of gas ~ 1,000 ~ 

Maximum gas demand for outlet C: 

Consumption _ 35,000 _ „ 
Btu of gas ~ 1,000 ~ 

Maximum gas demand for outlet D: 

Consumption 100,000 ,„„ _ 

= = 100 cfh 

Btu of gas 1,000 



o 
t; 
o 
o 



2 
a. 

















1 /2 




% 






1 


1'/4 




Vk 




2 




Vk 
















J 












/ 




1 




1 




















/ 












/ 




/ 






' 


















/ 












/ 




' 






/ 


















/ 












/ 










f 


















/ 












/ 










/ 


















/ 












/ 








1 


r- 


















l 












1 

1 , 




/ 




1 




i 


2 












, 


f J 










ft 


1 I 






/ 
















/ 


/ 










.£ 
? 








/ 




















/ 










' i 






































s 


















, 4 










/ 


















I / 












' 


0.6 
0.5 








y 










?f 








/ 










1 


" 






A 


r 










■0 f 






t 












/ 








/ 










/ T 




























/ 






/ 
























/ 








/ 








f 


/ s / 

/ ® / 

/ 0) / 


























/ 


/ 








, 


1 $ 

t 1 




























/ 










/ 


























1 b 




/ 










/ 


























1 




/ 










f 
























/ 






/ 


/ 






/ 


























/ 




0.05 


/ 


/ 






/ 


























/ 




/ 


/ 




/ 




























/ 




0.03 

0.02 


f 


/ 




/ 


















/ / 








1 


' 




/ 




/ 






, 


1 1 










1 


/ 








1 




, 8 


/ 




' 




/ 


I 


1 1 








/ 


/ 


/ 




/ 


/ 




1 

/ 




1 


2 


3 


4 


5 


06 


8< 


)100 2C 





4 


10 


6 


)0 80 


L10OO 20 


00 


40 


00 


6C 


00 1 


0,000 



Gas volume (standard ft 3 /hr gas SpGr = 0.60) 
FIGURE C.7(a) Capacity of Natural Gas Piping, Low Pressure (0.60 in. w.c). 



2006 Edition 



54-128 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-128 



1000 
9 
8 

7 

6 
5 



100 
9 
8 
7 
6 
5 



Index number = 



Dist. 



(100) 



Dist. = Eq. length, ft 

P 1 = Initial press, abs. psi -| 

P 2 = Final press, abs. psi -j 

7 
6 
5 



1.0 







%" 

7 = 


1" VI 

-t h 


." 1 


A" 2" 


Z'/2 3" 




4" 5 


6" 


8" 


10" 12" 

77 -T " 






t- - 


—f V- 






■/---^ 




~£ 






i- *--- 








/ 






/ 




jL 






/ 








1 J 






I 




f f_ 














1 1 






1 i 


















1 1 






1 / 
















/ 1 


1 / 1 




J 1 


< / 

i / 


















T — / 




































/ / 
















/ 








1 / 
















1 1 






Lt'U-TT 














/ 


/ 


i T 




7 j 


1 










/ I 


' / J 


/ 


\J- i 


i 

> i 




-J / 


1 

1 

1 










t~ 
























1 - 
























r > 


1 / 






















/ 






7 i 


i 1 
















/ 


/ / 




I r 
J- J- 
















/ 




I / 




{ 


/ / 












' I 


/ 


/ 1 


1 / 




f 

/ 


// 


/ 











1000 



10,000 100,000 1,000,000 

Gas volume (standard ft 3 /hr gas specific gravity = 0.60) 



FIGURE C.7(b) Capacity of Natural Gas Piping, High Pressure (1.5 psi and above). 



Section 3 



Outlet C • — 

40 gal automatic 
water heater 
35,000 Btu/hr 



20 ft 



10ft 



Outlet D 
furnace 
100,000 Btu/hr 



Section 2 



20 ft 

Section 1 
10ft 



15ft 



Point of 
delivery 



>15 ft 



5 ft 



Outlet A 
clothes dryer 
35,000 Btu/hr 



Outlet B 
range/oven unit 
75,000 Btu/hr 

For SI units, 1 ft = 0.305 m, 1 gal = 3.785 L, 1000 Btu/hr = 0.293 kW. 

FIGURE C.8. 1 Piping Plan Showing a Steel Piping System. 



(2) The length of pipe from the point of delivery to the most 
remote outlet (A) is 60 ft (18.3 m). This is the only distance 
used. 

(3) Using the row marked 60 ft (18.3 m) in Table 6.2(b): 

(a) Outlet A, supplying 35 cfh (0.99 m 3 /hr), requires 
Vi in. pipe. 

(b) Outlet B, supplying 75 cfh (2.12 m 3 /hr), requires 
% in. pipe. 

(c) Section 1, supplying outlets A and B, or 110 cfh 
(3.11 m 3 /hr), requires % in. pipe. 

(d) Section 2, supplying outlets C and D, or 135 cfh 
(3.82 m 3 /hr), requires % in. pipe. 

(e) Section 3, supplying outlets A, B, C, and D, or 245 cfh 
(6.94 m s /hr), requires 1 in. pipe. 

(4) If a different gravity factor is applied to this example, the 
values in the row marked 60 ft (18.3 m) of Table 6.2(b) 
would be multiplied by the appropriate multiplier from 
Table C.3.4 and the resulting cubic feet per hour values 
would be used to size the piping. 

C.8.2 Example 2 — Hybrid or Dual Pressure Systems. Deter- 
mine the required CSST size of each section of the piping 
system shown in Figure C.8.2, with a designated pressure drop 
of 1 psi (7 kPa) for the 2 psi (14 kPa) section and 3 in. w.c. 
(0.75 kPa) pressure drop for the 10 in. w.c. (2.49 kPa) section. 
The gas to be used has 0.60 specific gravity and a heating value 
of 1000 Btu/ft 3 (37.5 MJ/nO . 



2006 Edition 



ANSIZ223.1-129 



ANNEX C 



54-129 



2 psi 

Gas meter 
110 cfh 




Length of runs: 
A = 100 ft 
B = 15ft 
C = 10ft 
D = 25ft 



Key: 

Ufa Manifold 
X Shutoff valve 
|><] Pressure regulator 
[m1 Gas meter 



FIGURE C.8.2 Piping Plan Showing a CSST System. 

Solution 

(1) Size 2 psi (14 kPa) line using Table 6.2(p). 

(2) Size 10 in. w.c. (2.5 kPa) lines using Table 6.2(n). 

(3) Using the following steps, determine if sizing tables can 
be used: 

(a) Total gas load shown in Figure C.8.2 equals 110 chf 
(3.11 m 3 /hr). 

(b) Determine pressure drop across regulator [see notes 
in Table 6.2(p)]. 

(c) If pressure drop across regulator exceeds % psi 
(5.2 kPa), Table 6.2(p) cannot be used. Note that if 
pressure drop exceeds % psi (5.2 kPa), a larger 
regulator must be selected or an alternative sizing 
method must be used. 

(d) Pressure drop across the line regulator [for 110 cfh/ 
(3.11 m 3 /hr)] is 4 in. w.c. (0.99 kPa) based on manu- 
facturer's performance data. 

(e) Assume the CSST manufacturer has tubing sizes or 
EHDsofl3, 18, 23, and 30. 

(4) From Section A [2 psi (14 kPa) zone]: 

(a) Determine distance from meter to regulator = 100 ft 
(30.48 m). 

(b) Determine total load supplied by A = 110 cfh 
(3.11 m 3 /hr) (furnace + water heater + dryer). 

(c) Table 6.2 (p) shows that EHD size 18 should be used. 
Note that it is not unusual to oversize the supply line 
by 25 to 50 percent of the as-installed load. EHD size 
18 has a capacity of 189 cfh (5.35 m 3 /hr) . 

(5) From Section B (low pressure zone): 

(a) Distance from regulator to furnace is 15 ft (4.57 m). 

(b) Load is 60 cfh (1.70 m 3 /hr). 

(c) Table 6.2(n) shows that EHD size 13 should be used. 

(6) From Section C (low pressure zone): 

(a) Distance from regulator to water heater is 10 ft (3 m) . 

(b) Load is 30 cfh (0.85 m 3 /hr) . 

(c) Table 6.2(n) shows that EHD size 13 should be used. 

(7) From Section D (low pressure zone): 



(a) Distance from regulator to dryer is 25 ft (7.62 m). 

(b) Load is 20 cfh (0.57 m 3 /hr). 

(c) Table 6.2(n) shows that EHD size 13 should be used. 

C.8.3 Example 3 — Branch Length Method. Determine the 
required semi-rigid copper tubing size of each section of the 
piping system shown in Figure C.8.3, with a designated pres- 
sure drop of 1 in. w.c. (250 Pa) (using the Branch Length 
Method). The gas to be used has 0.60 specific gravity and a 
heating value of 1,000 Btu/ft 3 (37.5 MJ/m 3 ). 

Solution 

(1) Section A: 

(a) The length of tubing from the point of delivery to the 
most remote appliance is 50 ft (15 m), A+ C. 

(b) Use this longest length to size Sections A and C. 

(c) Using the row marked 50 ft (15 m) in Table 6.2(h), 
Section A supplying 220 cfh (6.23 m 3 /hr) for four 
appliances requires 1 in. tubing. 

(2) Section B: 

(a) The length of tubing from the point of delivery to the 
range/oven at the end of Section B is 30 ft (9.14 m), 
A+B. 

(b) Use this branch length to size Section B only. 

(c) Using the row marked 30 ft (9.14 m) in Table 6.2(h), 
Section B supplying 75 cfh (2.12 m 3 /hr) for the 
range/oven requires l A in. tubing. 

(3) Section C: 

(a) The length of tubing from the point of delivery to the 
dryer at the end of Section C is 50 ft (15 m), A + C. 

(b) Use this branch length (which is also the longest 
length) to size Section C. 

(c) Using the row marked 50 ft (15 m) in Table 6.2(h), 
Section C supplying 30 cfh (0.85 m 3 /hr) for the dryer 
requires % in. tubing. 

(4) Section D: 

(a) The length of tubing from the point of delivery to the 
water heater at the end of Section D is 30 ft (9.14 m), 
A+D. 

(b) Use this branch length to size Section D only. 



Section B T 

Section A X~~\ Section D 
220 cfh ^^ ^^ water 

Section E *-*/ ) nea t er 
X W 35 cfh 



go Range/oven 
00 75 cfh 



Section C 



Furnace 
80 cfh 



Dryer 
30 cfh 



Length of runs: 
A = 20 ft 
B = 10ft 
C = 30ft 
D = 10ft 
E = 10 ft 



Key: 



Manifold 
X Shutoff valve 
[m] Gas meter 
Total gas load = 220 cfh 



FIGURE C.8.3 Piping Plan Showing a Copper Tubing System. 



2006 Edition 



54-130 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-130 



(c) Using the row marked 30 ft (9.14 m) in Table 6.2(h), 
Section D supplying 35 cfh (34.69 m 3 /hr) for the wa- 
ter heater requires % in. tubing. 
(5) Section E: 

(a) The length of tubing from the point of delivery to the 
furnace at the end of Section E is 30 ft (9.14 m), A+ E. 

(b) Use this branch length to size Section E only. 

(c) Using the row marked 30 ft (9.14 m) in Table 6.2(h), 
Section E supplying 80 cfh (0.99 m 3 /hr) for the fur- 
nace requires V2 in. tubing. 

C.8.4 Example 4 — Modification to Existing Piping System. 

Determine the required CSST size for Section G (retrofit ap- 
plication) of the piping system shown in Figure C.8.4, with a 
designated pressure drop of 0.50 in. w.c. (125 Pa) using the 
Branch Length Method. The gas to be used has 0.60 specific 
gravity and a heating value of 1,000 Btu/ft 3 (37.5 MJ/m 3 ). 

Solution 
( 1 ) The length of pipe and CSST from the point of delivery to 

the retrofit appliance (barbecue) at the end of Section G 

is40ft(12.19m),A+B + G. 

Use this branch length to size Section G. 

Assume the CSST manufacturer has tubing sizes or EHDs 

of 13, 18, 23, and 30. 
(4) Using the row marked 40 ft (12.19 m) in Table 6.2(m), 

Section G supplying 40 cfh (1.13 m 3 /hr) for the barbecue 

requires EHD 18 CSST. 

The sizing of Sections A, B, F, and E must be checked to 

ensure adequate gas carrying capacity since an appliance has 

been added to the piping system. See C.8.1 for details. 



(2) 
(3) 



(5) 



C.8.5 Example 5 — Calculating Pressure Drops Due to Tem- 
perature Changes. A test piping system is installed on a warm 
autumn afternoon when the temperature is 70 degrees. In accor- 
dance with local custom, the new piping system is subjected to an 
air pressure test at 20 psig. Overnight, the temperature drops, 
and when the inspector shows up first thing in the morning the 
temperature is 40 degrees. 











Barbecue 

40 cfh 

R71 










M 




Section A S 


O 
O 
O 

O 
O 
O 

C 

ection B = 


Section G 
Sec 


ion C 






Section F 

) 


C 


I Section E 



Water 

heater 

e 30 cfh 

1 


Section D 

) 


C 










F 


urnac 
30 eft 


Rang 





e/ov 
cfh 


en 




.ength of runs: 
A = 15 ft E = 
B = 10ft F = 
C = 15ft G = 
D = 20ft 


5f 
10 
15 


t 

ft 
ft 






Key: 
X S 

[m] g 


hutoff valve 
as meter 









If the volume of the piping system is unchanged, the for- 
mula based on Boyle's and Charles' law for determining the 
new pressure at a reduced temperature is as follows: 

(1) 

T X _P, 



where: 

T l = initial temperature, absolute (7\ + 459) 
final temperature, absolute (T 2 + 459) 
initial pressure, psia (P 1 + 14.7) 

P 2 = final pressure, psia (P 2 + 14.7) 



FIGURE C.8.4 Piping Plan Showing Modification to an 
Existing Piping System. 



-Pi 

(2) 



(70 + 459) _ (20 + 14.7) 
(40 + 459) ~(P 2 +14.7) 



(3) 



(4) 



529 



34.7 



499 (P. + 14.7) 



(P 2 +14.7) = ^ 
v 2 ; 1.06 



P 2 = 32.7 - 



14.7 



P 2 = 18 psig 

Therefore, you could expect the gauge to register 18 psig 
when the ambient temperature is 40°F. 

C.8.6 Example 6 — Pressure Drop per 100 ft of Pipe Method. 

Using the layout shown in Figure C.8.1 and AH = pressure 
drop, in. w.c. (27.7 in. H 2 =1 psi), proceed as follows: 

(1) Length to A = 20 ft, with 35,000 Btu/hr: 

For '/a in. pipe: AH= 20 ft/100 ft x 0.3 in. w.c. = 0.06 in. w.c. 

(2) Length to B = 15 ft, with 75,000 Btu/hr: 

For % in. pipe: AH= 15 ft/100 ft x 0.3 in. w.c. = 0.045 in. w.c. 

(3) Section 1 = 10 ft, with 110,000 Btu/hr. Here there is a choice: 

For 1 in. pipe: AH= 10 ft/100 ft x 0.2 in. w.c. = 0.02 in. w.c. 

For % in. pipe: AH = 10 ft/100 ft x [0.5 in. w.c. + 
(110,000 Btu/hr - 104,000 Btu/hr)/(147,000 Btu/hr - 
104,000 Btu/hr) x (1.0 in. w.c. - 0.5 in. w.c.)] = 0.1 x 
0.57 in. w.c = 0.06 in. w.c. 

Notice that the pressure drop for 110,000 Btu/hr between 104,000 
Btu/hr and 147, 000 Btu/hr has been interpolated. 

(4) Section 2 = 20 ft, with 135,000 Btu/hr. Here there is a choice: 

For 1 in. pipe: AH = 20 ft/100 ft x [0.2 in. w.c. + (A14,000 
Btu/hr/ A27,000 Btu/hr x A0.1 in. w.c)] = 0.05 in. w.c. 

For % in. pipe: AH= 20 ft/100 ft x 1.0 in. w.c. = 0.2 in. w.c. 

Notice that thepressure drop for 135,000 Btu/hr between 121,000 
Btu/hr and 148,000 Btu/hr has been interpolated, but interpola- 
tion was not used for the 3 A in. pipe (trivial for 104,000 Btu/hr to 
147,000 Btu/hr). 

(5) Section 3 = 30 ft, with 245,000 Btu/hr. Here there is a choice: 
For 1 in. pipe: AH= 30 ft/100 ft x 1.0 in. w.c. = 0.3 in. w.c. 



2006 Edition 



ANSIZ223.1-131 



ANNEX D 



54-131 



For 1 Vi in. pipe: AH= 30 ft/100 ft x 0.2 in. w.c. = 0.06 in. w.c. 

Notice that interpolation was not used for these options, since the 
table values are close to the 245, 000 Biu/hr carried by that section. 

(6) The total pressure drop is the sum of the section approach- 
ing A, Section 1, and Section 3, or either of the following, 
depending on whether an absolute minimum is required or 
the larger drop can be accommodated: 

Minimum Pressure Drop to farthest appliance: 

AH= 0.06 in. w.c. + 0.02 in. w.c. + 0.06 in. w.c = 0.14 in. w.c. 

Larger Pressure Drop to the farthest appliance: 

AH= 0.06 in. w.c. + 0.06 in. w.c. + 0.3 in. w.c. = 0.42 in. w.c. 

Notice that Section 2 and the run toBdo not enter into this calcula- 
tion, provided that the appliances have similar input pressure re- 
quirements. 

For SI units: 1 Btu/hr = 0.293 W, 1 ft 3 = 0.028 m 3 , 1 ft = 0.305 m, 
1 in. w.c. = 249 Pa. 



Annex D Suggested Method of Checking for Leakage 

This annex is not apart of the requirements of this NFPA document 
but is included for informational purposes only. 

D.l Use of Lights. Artificial illumination used in connection 
with a search for gas leakage should be restricted to battery- 
operated flashlights (preferably of the safety type) or ap- 
proved safety lamps. In searching for leaks, electric switches 
should not be operated. If electric lights are already turned 
on, they should not be turned off. 

D.2 Leak Check Using the Gas Meter. Immediately prior to 
the leak check, it should be determined that the meter is in 
operating condition and has not been bypassed. 

The leak check can be done by carefully watching the test dial 
of the meter to determine whether gas is passing through the 
meter. To assist in observing any movement of the test hand, wet 
a small piece of paper and paste its edge directly over the center- 
line of the hand as soon as the gas is turned on. This observation 
should be made with the test hand on the upstroke. Table D.2 
can be used for determining the length of observation time. 



Table D.2 
Meter Dials 



Observation Times for Various 



Dial Styles 

(ft 3 ) 



Test Time 
(min) 



V4 

y 2 



l 

2 

5 

10 



5 

5 

7 

10 

20 

30 



For SI units, 1 ft 3 = 0.028 m 3 . 

In case careful observation of the test hand for a sufficient 
length of time reveals no movement, the piping should be 
purged and a small gas burner turned on and lighted and the 
hand of the test dial again observed. If the dial hand moves (as 



it should), it will show that the meter is operating properly. If 
the test hand does not move or register flow of gas through the 
meter to the small burner, the meter is defective and the gas 
should be shut off and the serving gas supplier notified. 

D.3 Leak Check Not Using a Meter. This test can be done 
using one of the following methods: 

(1) For Any Gas System. To an appropriate checkpoint, attach 
a manometer or pressure gauge between the inlet to the 
piping system and the first regulator in the piping system, 
momentarily turn on the gas supply, and observe the 
gauging device for pressure drop with the gas supply shut 
off. No discernible drop in pressure should occur during 
a period of 3 minutes. 

(2) For Gas Systems Using Undiluted Liquefied Petroleum Gas System 
Preparation for Propane. A leak check performed on an LP- 
Gas system being placed back in service should include all 
regulators, including appliance regulators, and control 
valves in the system. Accordingly, each individual appliance 
shutoff valve should be supplying pressure to its appliance 
for the leak check. This check will prove the integrity of the 
100 percent pilot shutoff of each gas valve so equipped, so 
the manual gas cock of each gas valve incorporating a 
100 percent pilot shutoff should be in the on position. Pilots 
not incorporating a 100 percent pilot shutoff valve and all 
manual gas valves not incorporating safety shutoff systems 
are to be placed in the off position prior to leak checking, by 
using one of the following methods: 

(a) By inserting a pressure gauge between the container gas 
shutoff valve and the first regulator in the system, admit- 
ting full container pressure to the system and then clos- 
ing the container shutoff valve. Enough gas should then 
be released from the system to lower the pressure gauge 
reading by 10 psi (69 kPa). The system should then be 
allowed to stand for 3 minutes without showing an in- 
crease or a decrease in the pressure gauge reading. 

(b) For systems serving appliances that receive gas at pres- 
sures of M> psi (3.5 kPa) or less, by inserting a water 
manometer or pressure gauge into the system down- 
stream of the final system regulator, pressurizing the 
system with either fuel gas or air to a test pressure of 
9 in. w.c. ± Vz in. w.c. (2.2 kPa ± 0.1 kPa), and observ- 
ing the device for a pressure change. If fuel gas is 
used as a pressure source, it is necessary to pressurize 
the system to full operating pressure, close the con- 
tainer service valve, and then release enough gas 
from the system through a range burner valve or 
other suitable means to drop the system pressure to 
9 in. w.c. ± Vi in. w.c. (2.2 kPa ± 0.1 kPa). This ensures 
that all regulators in the system are unlocked and that 
a leak anywhere in the system is communicated to the 
gauging device. The gauging device should indicate 
no loss or gain of pressure for a period of 3 minutes. 

(c) By inserting a 30 psi (207 kPa) pressure gauge on the 
downstream side of the first stage regulator, admitting 
normal operating pressure to the system and then clos- 
ing the container valve. Enough pressure should be re- 
leased from the system to lower the pressure gauge 
reading by 5 psi (34.5 kPa). The system should be al- 
lowed to stand for 3 minutes without showing an in- 
crease or a decrease in pressure gauge reading. 

D.4 When Leakage Is Indicated. If the meter test hand moves 
or a pressure drop on the gauge is noted, all appliances and 
equipment or outlets supplied through the system should be 
examined to see whether they are shut off and do not leak. If 
they are found to be tight, there is a leak in the piping system. 



2006 Edition 



54-132 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-132 



Annex E Suggested Emergency Procedure 
for Gas Leaks 

This annex is not a part of the requirements of this NFPA document 
but is included for informational purposes only. 

E.l Where an investigation discloses a concentration of gas 
inside of a building, it is suggested the following immediate 
actions be taken: 

(1) Clear the room, building, or area of all occupants. Do not 
re-enter the room, building, or area until the space has 
been determined to be safe. 

(2) Use every practical means to eliminate sources of ignition. 
Take precautions to prevent smoking, striking matches, op- 
erating electrical switches or devices, opening furnace 
doors, and so on. If possible, cut off all electric circuits at a 
remote source to eliminate operation of automatic switches 



in the dangerous area. Safety flashlights designed for use in 
hazardous atmospheres are recommended for use in such 
emergencies. 

(3) Notify all personnel in the area and the gas supplier from 
a telephone remote from the area of the leak. 

(4) Ventilate the affected portion of the building by opening 
windows and doors. 

(5) Shut off the supply of gas to the areas involved. 

(6) Investigate other buildings in the immediate area to de- 
termine the presence of escaping gas therein. 



Annex F Flow of Gas Through Fixed Orifices 

This annex is not apart of the requirements of this NFPA document 
but is included for informational purposes only. 

F.l Use of Orifice Tables. 



Table F. 1 (a) Utility Gases (cubic feet per hour at sea level) 











Pressure at Orifice (in. 


w.c.) 




























Drill Size 


3 


3.5 


4 


5 


6 


7 


8 


9 


10 


80 


0.48 


0.52 


0.55 


0.63 


0.69 


0.73 


0.79 


0.83 


0.88 


79 


0.55 


0.59 


0.64 


0.72 


0.80 


0.84 


0.90 


0.97 


1.01 


78 


0.70 


0.76 


0.78 


0.88 


0.97 


1.04 


1.10 


1.17 


1.24 


77 


0.88 


0.95 


0.99 


1.11 


1.23 


1.31 


1.38 


1.47 


1.55 


76 


1.05 


1.13 


1.21 


1.37 


1.52 


1.61 


1.72 


1.83 


1.92 


75 


1.16 


1.25 


1.34 


1.52 


1.64 


1.79 


1.91 


2.04 


2.14 


74 


1.33 


1.44 


1.55 


1.74 


1.91 


2.05 


2.18 


2.32 


2.44 


73 


1.51 


1.63 


1.76 


1.99 


2.17 


2.32 


2.48 


2.64 


2.78 


72 


1.64 


1.77 


1.90 


2.15 


2.40 


2.52 


2.69 


2.86 


3.00 


71 


1.82 


1.97 


2.06 


2.33 


2.54 


2.73 


2.91 


3.11 


3.26 


70 


2.06 


2.22 


2.39 


2.70 


2.97 


3.16 


3.38 


3.59 


3.78 


69 


2.25 


2.43 


2.61 


2.96 


3.23 


3.47 


3.68 


3.94 


4.14 


68 


2.52 


2.72 


2.93 


3.26 


3.58 


3.88 


4.14 


4.41 


4.64 


67 


2.69 


2.91 


3.12 


3.52 


3.87 


4.13 


4.41 


4.69 


4.94 


66 


2.86 


3.09 


3.32 


3.75 


4.11 


4.39 


4.68 


4.98 


5.24 


65 


3.14 


3.39 


3.72 


4.28 


4.62 


4.84 


5.16 


5.50 


5.78 


64 


3.41 


3.68 


4.14 


4.48 


4.91 


5.23 


5.59 


5.95 


6.26 


63 


3.63 


3.92 


4.19 


4.75 


5.19 


5.55 


5.92 


6.30 


6.63 


62 


3.78 


4.08 


4.39 


4.96 


5.42 


5.81 


6.20 


6.59 


6.94 


61 


4.02 


4.34 


4.66 


5.27 


5.77 


6.15 


6.57 


7.00 


7.37 


60 


4.21 


4.55 


4.89 


5.52 


5.95 


6.47 


6.91 


7.35 


7.74 


59 


4.41 


4.76 


5.11 


5.78 


6.35 


6.78 


7.25 


7.71 


8.11 


58 


4.66 


5.03 


5.39 


6.10 


6.68 


7.13 


7.62 


8.11 


8.53 


57 


4.84 


5.23 


5.63 


6.36 


6.96 


7.44 


7.94 


8.46 


8.90 


56 


5.68 


6.13 


6.58 


7.35 


8.03 


8.73 


9.32 


9.92 


10.44 


55 


7.11 


7.68 


8.22 


9.30 


10.18 


10.85 


11.59 


12.34 


12.98 


54 


7.95 


8.59 


9.23 


10.45 


11.39 


12.25 


13.08 


13.93 


14.65 


53 


9.30 


10.04 


10.80 


12.20 


13.32 


14.29 


15.27 


16.25 


17.09 


52 


10.61 


11.46 


12.31 


13.86 


15.26 


16.34 


17.44 


18.57 


19.53 


51 


11.82 


12.77 


13.69 


15.47 


16.97 


18.16 


19.40 


20.64 


21.71 


50 


12.89 


13.92 


14.94 


16.86 


18.48 


19.77 


21.12 


22.48 


23.65 


49 


14.07 


15.20 


16.28 


18.37 


20.20 


21.60 


23.06 


24.56 


25.83 


48 


15.15 


16.36 


17.62 


19.88 


21.81 


23.31 


24.90 


26.51 


27.89 


47 


16.22 


17.52 


18.80 


21.27 


23.21 


24.93 


26.62 


28.34 


29.81 


46 


17.19 


18.57 


19.98 


22.57 


24.72 


26.43 


28.23 


30.05 


31.61 



2006 Edition 



ANSI Z223.1-133 



ANNEX F 



54-133 



Table F. 1 (a) Continued 










Pressure at Orifice (in. 


w.c.) 




























Drill Size 


3 


3.5 


4 


5 


6 


7 


8 


9 


10 


45 


17.73 


19.15 


20.52 


23.10 


25.36 


27.18 


29.03 


30.90 


32.51 


44 


19.45 


21.01 


22.57 


25.57 


27.93 


29.87 


31.89 


33.96 


35.72 


43 


20.73 


22.39 


24.18 


27.29 


29.87 


32.02 


34.19 


36.41 


38.30 


42 


23.10 


24.95 


26.50 


29.50 


32.50 


35.24 


37.63 


40.07 


42.14 


41 


24.06 


25.98 


28.15 


31.69 


34.81 


37.17 


39.70 


42.27 


44.46 


40 


25.03 


27.03 


29.23 


33.09 


36.20 


38.79 


41.42 


44.10 


46.38 


39 


26.11 


28.20 


30.20 


34.05 


37.38 


39.97 


42.68 


45.44 


47.80 


38 


27.08 


29.25 


31.38 


35.46 


38.89 


41.58 


44.40 


47.27 


49.73 


37 


28.36 


30.63 


32.99 


37.07 


40.83 


43.62 


46.59 


49.60 


52.17 


36 


29.76 


32.14 


34.59 


39.11 


42.76 


45.77 


48.88 


52.04 


54.74 


35 


32.36 


34.95 


36.86 


41.68 


45.66 


48.78 


52.10 


55.46 


58.34 


34 


32.45 


35.05 


37.50 


42.44 


46.52 


49.75 


53.12 


56.55 


59.49 


33 


33.41 


36.08 


38.79 


43.83 


48.03 


51.46 


54.96 


58.62 


61.55 


32 


35.46 


38.30 


40.94 


46.52 


50.82 


54.26 


57.95 


61.70 


64.89 


31 


37.82 


40.85 


43.83 


49.64 


54.36 


58.01 


61.96 


65.97 


69.39 


30 


43.40 


46.87 


50.39 


57.05 


62.09 


66.72 


71.22 


75.86 


79.80 


29 


48.45 


52.33 


56.19 


63.61 


69.62 


74.45 


79.52 


84.66 


89.04 


28 


51.78 


55.92 


59.50 


67.00 


73.50 


79.50 


84.92 


90.39 


95.09 


27 


54.47 


58.83 


63.17 


71.55 


78.32 


83.59 


89.27 


95.04 


99.97 


26 


56.73 


61.27 


65.86 


74.57 


81.65 


87.24 


93.17 


99.19 


104.57 


25 


58.87 


63.58 


68.22 


77.14 


84.67 


90.36 


96.50 


102.74 


108.07 


24 


60.81 


65.67 


70.58 


79.83 


87.56 


93.47 


99.83 


106.28 


111.79 


23 


62.10 


67.07 


72.20 


81.65 


89.39 


94.55 


100.98 


107.49 


113.07 


22 


64.89 


70.08 


75.21 


85.10 


93.25 


99.60 


106.39 


113.24 


119.12 


21 


66.51 


71.83 


77.14 


87.35 


95.63 


102.29 


109.24 


116.29 


122.33 


20 


68.22 


73.68 


79.08 


89.49 


97.99 


104.75 


111.87 


119.10 


125.28 


19 


72.20 


77.98 


83.69 


94.76 


103.89 


110.67 


118.55 


125.82 


132.36 


18 


75.53 


81.57 


87.56 


97.50 


108.52 


116.03 


123.92 


131.93 


138.78 


17 


78.54 


84.82 


91.10 


103.14 


112.81 


120.33 


128.52 


136.82 


143.91 


16 


82.19 


88.77 


95.40 


107.98 


118.18 


126.78 


135.39 


144.15 


151.63 


15 


85.20 


92.02 


98.84 


111.74 


122.48 


131.07 


139.98 


149.03 


156.77 


14 


87.10 


94.40 


100.78 


114.21 


124.44 


133.22 


142.28 


151.47 


159.33 


13 


89.92 


97.11 


104.32 


118.18 


128.93 


138.60 


148.02 


157.58 


165.76 


12 


93.90 


101.41 


108.52 


123.56 


135.37 


143.97 


153.75 


163.69 


172.13 


11 


95.94 


103.62 


111.31 


126.02 


137.52 


147.20 


157.20 


167.36 


176.03 


10 


98.30 


106.16 


114.21 


129.25 


141.82 


151.50 


161.81 


172.26 


181.13 


9 


100.99 


109.07 


117.11 


132.58 


145.05 


154.71 


165.23 


175.91 


185.03 


8 


103.89 


112.20 


120.65 


136.44 


149.33 


160.08 


170.96 


182.00 


191.44 


7 


105.93 


114.40 


123.01 


139.23 


152.56 


163.31 


174.38 


185.68 


195.30 


6 


109.15 


117.88 


126.78 


142.88 


156.83 


167.51 


178.88 


190.46 


200.36 


5 


111.08 


119.97 


128.93 


145.79 


160.08 


170.82 


182.48 


194.22 


204.30 


4 


114.75 


123.93 


133.22 


150.41 


164.36 


176.18 


188.16 


200.25 


210.71 


3 


119.25 


128.79 


137.52 


156.26 


170.78 


182.64 


195.08 


207.66 


218.44 


2 


128.48 


138.76 


148.61 


168.64 


184.79 


197.66 


211.05 


224.74 


235.58 


1 


136.35 


147.26 


158.25 


179.33 


194.63 


209.48 


223.65 


238.16 


250.54 



For SI units, 1 Btu/hr = 0.293 W, 1 ft 3 = 0.028 m 3 , 1 ft = 0.305 m, 1 in. w.c. = 249 Pa. 
Notes: 

1. Specific gravity = 0.60; orifice coefficient = 0.90. 

2. For utility gases of another specific gravity, select multiplier from Table F.l (c) . For altitudes above 2000 ft, first select the 
equivalent orifice size at sea level from Table F.l (d) . 



2006 Edition 



54-134 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-134 



Table F. 1 (b) LP-Gases (Btu per hour at 
sea level) 



Table F. 1 (b) Continued 



Orifice or 
Drill Size 



0.008 
0.009 
0.010 
0.011 
0.012 



80 
79 
78 

77 
76 



75 
74 
73 
72 
71 



70 
69 
68 
67 
66 



65 
64 
63 
62 
61 



60 
59 
58 
57 
56 



55 
54 
53 
52 
51 



50 
49 
48 
47 
46 



45 
44 
43 
42 
41 



Propane 



519 
656 
812 
981 
1,169 



1,480 
1,708 
2,080 
2,629 
3,249 



3,581 
4,119 
4,678 
5,081 
5,495 



6,375 
6,934 
7,813 
8,320 
8,848 



9,955 
10,535 
11,125 
11,735 
12,367 



13,008 
13,660 
14,333 
15,026 
17,572 



21,939 
24,630 
28,769 
32,805 
36,531 



39,842 
43,361 
46,983 
50,088 
53,296 



54,641 
60,229 
64,369 
71,095 
74,924 



Butane 



589 

744 

921 

1,112 

1,326 



1,678 
1,936 
2,358 
2,980 
3,684 



4,059 
4,669 
5,303 
5,760 
6,230 



7,227 
7,860 
8,858 
9,433 
10,031 



11,286 
11,943 
12,612 
13,304 
14,020 



14,747 
15,486 
16,249 
17,035 
19,921 



24,872 
27,922 
32,615 
37,190 
41,414 



45,168 
49,157 
53,263 
56,783 
60,420 



61,944 
68,280 
72,973 
80,599 

84,940 



Orifice or 






Drill Size 


Propane 


Butane 


40 


78,029 


88,459 


39 


80,513 


91,215 


38 


83,721 


94,912 


37 


87,860 


99,605 


36 


92,207 


104,532 


35 


98,312 


111,454 


34 


100,175 


113,566 


33 


103,797 


117,672 


32 


109,385 


124,007 


31 


117,043 


132,689 


30 


134,119 


152,046 


29 


150,366 


170,466 


28 


160,301 


181,728 


27 


168,580 


191,114 


26 


175,617 


199,092 


25 


181,619 


205,896 


24 


187,828 


212,935 


23 


192,796 


218,567 


22 


200,350 


227,131 


21 


205,525 


232,997 


20 


210,699 


238,863 


19 


223,945 


253,880 


18 


233,466 


264,673 



Notes: 





Propane 


Butane 


1. Btu per cubic foot 


2,516 


3,280 


2. Specific gravity 


1.52 


2.01 


3. Pressure at orifice, in. w.c. 


11 


11 


4. Orifice coefficient 


0.9 


0.9 


5. For altitudes above 2000 ft (610 m), first select the equivalent orifice 


size at sea level from Table F. 1 (d) . 





Table F. 1 (c) Multipliers for Utility Gases of 
Another Specific Gravity 



Specific 




Specific 




Gravity 


Multiplier 


Gravity 


Multiplier 


0.45 


1.155 


0.95 


0.795 


0.50 


1.095 


1.00 


0.775 


0.55 


1.045 


1.05 


0.756 


0.60 


1.000 


1.10 


0.739 


0.65 


0.961 


1.15 


0.722 


0.70 


0.926 


1.20 


0.707 


0.75 


0.894 


1.25 


0.693 


0.80 


0.866 


1.30 


0.679 


0.85 


0.840 


1.35 


0.667 


0.90 


0.817 


1.40 


0.655 



2006 Edition 



ANSIZ223.1-135 



ANNEX F 



54-135 



Table F. 1 (d) Equivalent Orifice Sizes at High Altitudes (includes 4% input reduction 
for each 1000 ft above sea level) 



Orifice 






i 


Orifice Size Required at Other Elevations (ft) 




























Sea Level 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


10,000 


1 


2 


2 


3 


3 


4 


5 


7 


8 


10 


2 


3 


3 


4 


5 


6 


7 


9 


10 


12 


3 


4 


5 


7 


8 


9 


10 


12 


13 


15 


4 


6 


7 


8 


9 


11 


12 


13 


14 


16 


5 


7 


8 


9 


10 


12 


13 


14 


15 


17 


6 


8 


9 


10 


11 


12 


13 


14 


16 


17 


7 


9 


10 


11 


12 


13 


14 


15 


16 


18 


8 


10 


11 


12 


13 


13 


15 


16 


17 


18 


9 


11 


12 


12 


13 


14 


16 


17 


18 


19 


10 


12 


13 


13 


14 


15 


16 


17 


18 


19 


11 


13 


13 


14 


15 


16 


17 


18 


19 


20 


12 


13 


14 


15 


16 


17 


17 


18 


19 


20 


13 


15 


15 


16 


17 


18 


18 . 


19 


20 


22 


14 


16 


16 


17 


18 


18 


19 


20 


21 


23 


15 


16 


17 


17 


18 


19 


20 


20 


22 


24 


16 


17 


18 


18 


19 


19 


20 


22 


23 


25 


17 


18 


19 


19 


20 


21 


22 


23 


24 


26 


18 


19 


19 


20 


21 


22 


23 


24 


26 


27 


19 


20 


20 


21 


22 


23 


25 


26 


27 


28 


20 


22 


22 


23 


24 


25 


26 


27 


28 


29 


21 


23 


23 


24 


25 


26 


27 


28 


28 


29 


22 


23 


24 


25 


26 


27 


27 


28 


29 


29 


23 


25 


25 


26 


27 


27 


28 


29 


29 


30 


24 


25 


26 


27 


27 


28 


28 


29 


29 


30 


25 


26 


27 


27 


28 


28 


29 


29 


30 


30 


26 


27 


28 


28 


28 


29 


29 


30 


30 


30 


27 


28 


28 


29 


29 


29 


30 


30 


30 


31 


28 


29 


29 


29 


30 


30 


30 


30 


31 


31 


29 


29 


30 


30 


30 


30 


31 


31 


31 


32 


30 


30 


31 


31 


31 


31 


32 


32 


33 


35 


31 


32 


32 


32 


33 


34 


35 


36 


37 


38 


32 


33 


34 


35 


35 


36 


36 


37 


38 


40 


33 


35 


35 


36 


36 


37 


38 


38 


40 


41 


34 


35 


36 


36 


37 


37 


38 


39 


40 


42 


35 


36 


36 


37 


37 


38 


39 


40 


41 


42 


36 


37 


38 


38 


39 


40 


41 


41 


42 


43 


37 


38 


39 


39 


40 


41 


42 


42 


43 


43 


38 


39 


40 


41 


41 


42 


42 


43 


43 


44 


39 


40 


41 


41 


42 


42 


43 


43 


44 


44 


40 


41 


42 


42 


42 


43 


43 


44 


44 


45 


41 


42 


42 


42 


43 


43 


44 


44 


45 


46 


42 


42 


43 


43 


43 


44 


44 


45 


46 


47 


43 


44 


44 


44 


45 


45 


46 


47 


47 


48 


44 


45 


45 


45 


46 


47 


47 


48 


48 


49 


45 


46 


47 


47 


47 


48 


48 


49 


49 


50 


46 


47 


47 


47 


48 


48 


49 


49 


50 


50 


47 


48 


48 


49 


49 


49 


50 


50 


51 


51 


48 


49 


49 


49 


50 


50 


50 


51 


51 


52 


49 


50 


50 


50 


51 


51 


51 


52 


52 


52 


50 


51 


51 


51 


51 


52 


52 


52 


53 


53 



(continues) 



2006 Edition 



54-136 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-136 



Table F. 1 (d) Continued 



Orifice 






Orifice Size Required at Other Elevations (ft) 






p; . 








































Sea Level 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


10,000 


51 


51 


.52 


52 


52 


52 


53 


53 


53 


54 


52 


52 


53 


53 


53 


53 


53 


54 


54 


54 


53 


54 


54 


54 


54 


54 


54 


55 


55 


55 


54 


54 


55 


55 


55 


55 


55 


56 


56 


56 


55 


55 


55 


55 


56 


56 


56 


56 


56 


57 


56 


56 


56 


57 


57 


57 


58 


59 


59 


60 


57 


58 


59 


59 


60 


60 


61 


62 


63 


63 


58 


59 


60 


60 


61 


62 


62 


63 


63 


64 


59 


60 


61 


61 


62 


62 


63 


64 


64 


65 


60 


61 


61 


62 


63 


63 


64 


64 


65 


65 


61 


62 


62 


63 


63 


64 


65 


65 


66 


66 


62 


63 


63 


64 


64 


65 


65 


66 


66 


67 


63 


64 


64 


65 


65 


65 


66 


66 


67 


68 


64 


65 


65 


65 


66 


66 


66 


67 


67 


68 


65 


65 


66 


66 


66 


67 


67 


68 


68 


69 


66 


67 


67 


68 


68 


68 


69 


69 


69 


70 


67 


68 


68 


68 


69 


69 


69 


70 


70 


70 


68 


68 


69 


69 


69 


70 


70 


70 


71 


71 


69 


70 


70 


70 


70 


71 


71 


71 


72 


72 


70 


70 


71 


71 


71 


71 


72 


72 


73 


73 


71 


72 


72 


72 


73 


73 


73 


74 


74 


74 


72 


73 


73 


73 


73 


74 


74 


74 


74 


75 


73 


73 


74 


74 


74 


74 


75 


75 


75 


76 


74 


74 


75 


75 


75 


75 


76 


76 


76 


76 


75 


75 


76 


76 


76 


76 


77 


77 


77 


77 


76 


76 


76 


77 


77 


77 


77 


77 


77 


77 


77 


77 


77 


77 


78 


78 


78 


78 


78 


78 


78 


78 


78 


78 


79 


79 


79 


79 


80 


80 


79 


79 


80 


80 


80 


80 


0.013 


0.012 


0.012 


0.01 


80 


80 


0.013 


0.013 


0.013 


0.012 


0.012 


0.012 


0.012 


0.011 



For SI units, 1 ft = 0.305 m. 



F.l.l To Check Burner Input not Using a Meter. Gauge the 
size of the burner orifice and determine flow rate at sea 
level from Table F.l (a), Utility Gases (cubic feet per hour), 
or from Table F.l(b), LP-Gases (Btu per hour). When the 
specific gravity of the utility gas is other than 0.60, select the 
multiplier from Table F.l(c) for the specific gravity of the 
utility gas served, and apply to the flow rate as determined 
from Table F.l (a). When the altitude is above 2000 ft (600 
m), first select the equivalent orifice size at sea level using 
Table F.l(d), then determine the flow rate from Table 
F.l (a) or Table F.l(b) as directed. Having determined the 
flow rate (as adjusted for specific gravity and/or altitude 
where necessary) , check the burner input at sea level with 
the manufacturer's rated input. 

F.l. 2 To Select Correct Orifice Size for Rated Burner Input. 

The selection of a fixed orifice size for any rated burner input 
is affected by many variables, including orifice coefficient, and 
it is recommended that the appliance manufacturer be con- 
sulted for that purpose. When the correct orifice size cannot 



be readily determined, the orifice flow rates, as stated in the 
tables in this annex, can be used to select a fixed orifice size 
with a flow rate to approximately equal the required rated 
burner input. 

For gases of the specific gravity and pressure conditions 
stipulated at elevations under 2000 ft (600 m) , Table F.l (a) (in 
cubic feet per hour) or Table F.l (b) (in Btu per hour) can be 
used directly. 

Where the specific gravity of the gas is other than 0.60, 
select the multiplier from Table F.l (c) for the utility gas served 
and divide the rated burner input by the selected factor to 
determine equivalent input at a specific gravity of 0.60, then 
select orifice size as directed above. 

Where the appliance is located at an altitude of 2000 ft 
(600 m) or above, first use the manufacturer's rated input at sea 
level to select the orifice size as directed, then use Table F.l (d) to 
select the equivalent orifice size for use at the higher altitude. 



2006 Edition 



ANSIZ223.1-137 



ANNEX G 



54-137 



Annex G Sizing of Venting Systems Serving 

Appliances Equipped with Draft Hoods, Category I 

Appliances, and Appliances Listed for Use 

with Type B Vents 

This annex is not a part of the requirements of this NFPA document 
but is included for informational purposes only. 

G. 1 Examples Using Single Appliance Venting Tables. See Fig- 
ure G.l(a) through Figure G.l(n). 



Vent cap - 



TypeB 
double-wall - 
gas vent 












i. 


Tile-lined masonry — > 
chimney 








Type B double-wall (t 




,| 


/■ 


V 


i 


'I 










gas vent used as -»■ 


t 






connector 


D 












A 


V 




E: 


=i 
















1 





Table 13.1 (a) is used when sizing Type B double-wall 
gas vent connected directly to the appliance. 

Note: The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(a) Type B Double-Wall Vent System Serving a 
Single Appliance with a Type B Double-Wall Vent. 



Table 13.1(c) is used when sizing a Type B double-wall 
gas vent connector attached to a tile-lined masonry 
chimney. 

Notes: 

1 . A is the equivalent cross-sectional area of the tile liner. 

2. The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (c) Vent System Serving a Single Appliance with a 
Masonry Chimney and a Type B Double-Wall Vent Connector. 



Vent cap — >-CZ3 _^ 



TypeB 
double-wall 
gas vent 



Single-wall — » 
vent connector 












n " 


Tile-lined masonry — * 
chimney 












J 




y 


\ 


*l 








Single-wall ► 

vent connector 


[ t 

D 


' 




Q. 


\ 


A 


















1 





Table 13.1(b) is used when sizing a single-wall metal 
vent connector attached to a Type B double-wall gas vent. 

Note: The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 



Table 13.1(d) is used when sizing a single-wall vent 
connector attached to a tile-lined masonry chimney. 

Notes: 

1 . A is the equivalent cross-sectional area of the tile liner. 

2. The appliance can be either Category I draft 
hood-equipped or fan-assisted type. 



FIGURE G.l(b) Type B Double-Wall Vent System Serving a 
Single Appliance with a Single-Wall Metal Vent Connector. 



FIGURE G. 1 (d) Vent System Serving a Single Appliance Using 
a Masonry Chimney and a Single-Wall Metal Vent Connector. 



2006 Edition 



54-138 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-138 



Vent cap 




Vent cap 



Type B double-wall 
common vent' 




Asbestos cement Type B or single-wall metal vent 
serving a single draft hood-equipped appliance. 
[See Table 13.1(e).] 

FIGURE G. 1 (e) Asbestos Cement Type B or Single-Wall Metal 
Vent System Serving a Single Draft Hood-Equipped Appliance. 



Table 13.2(b) is used when sizing single-wall vent 
connectors attached to a Type B double-wall 
common vent. 

Note: Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(g) Vent System Serving Two or More Appli- 
ances with Type B Double-Wall Vent and Single-Wall Metal 
Vent Connectors. 




TypeB 
double-wall 
gas vent used 
as connectors 



, 


. 
















h 


TypeB 
double-w 
gas vent 
used as 
connecto 

\ 


all _) 
rs 


A 


< — Tile-lined masonry 
chimney 




'^A~ 




j j_ 






■ t 






■4- 


\ 


Connector 
rise Ft 






-t- 


)l 




' 


' 






D 


h 
















iU s_ 








1 


t 


=J 





Table 13.2(a) is used when sizing Type B double-wall 
gas vent connectors attached to a Type B 
double-wall common vent. 

Note: Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G. 1 (f) Vent System Serving Two or More Appliances 
with Type B Double-Wall Vent and Type B Double-Wall Vent 
Connectors. 



Table 13.2(c) is used when sizing Type B double-wall 
vent connectors attached to a tile-lined masonry chimney. 

Notes: 

1 . A is the equivalent cross-sectional area of the tile liner. 

2. Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(h) Masonry Chimney Serving Two or More 
Appliances with Type B Double-Wall Vent Connectors. 



2006 Edition 



ANSIZ223.1-139 



ANNEX G 



54-139 



, 


I 




















< — Tile-lined masonry 
chimney 






A 




h 


, Single-wa 
connector 

X 

t 


1 vent 










r t 

D 




1 


i. i 
v Connector 


, 








1 


f Y rise f 
D 


• 




















1 




5^ 












1 









Table 13.2(d) is used when sizing single-wall metal vent 
connectors attached to a tile-lined masonry chimney. 

Notes: 

1 . A is the equivalent cross-sectional area of the tile liner. 

2. Each appliance can be either Category I draft 
hood-equipped or fan-assisted type. 

FIGURE G.l(i) Masonry Chimney Serving Two or More 
Appliances with Single-Wall Metal Vent Connectors. 





- 




vent connector \J 

K , 
r ...j 






n A y- ■ u 

d Connectors 


1 


1 




f 


f 2 | 




' 























1 




2 







Example: Manifolded common vent connector Lm can 
be no greater than 18 times the common vent connector 
manifold inside diameter; that is, a 4 in. (100 mm) inside 
diameter common vent connector manifold should not 
exceed 72 in. (1800 mm) in length. (See 13.2.4.) 

Note: This is an illustration of a typical manifolded vent 
connector. Different appliance, vent connector, or 
common vent types are possible. (See Section 13.2.) 

FIGURE G. 1 (k) Use of Manifolded Common Vent Connector. 



& 



See 
13.2.5. 



-Lo- H 



-Vent cap 



^ 



Asbestos cement Type B or single-wall metal pipe vent 
serving two or more draft hood-equipped appliances. 
[See Table 13.2(e).] 

FIGURE G. 1 (j) Asbestos Cement Type B or Single-Wall Metal 
Vent System Serving Two or More Draft Hood-Equipped 
Appliances. 



Vent cap 




Example: Offset common vent 

Note: This is an illustration of a typical offset vent. 
Different appliance, vent connector, or vent types are 
possible. (See Sections 13. 1. and 13.2.) 

FIGURE G. 1 (1) Use of Offset Common Vent. 



2006 Edition 



54-140 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-140 



Vent connector Tee 



\ 



C^> 



Common vent size 

based on all inputs * 

entering this segment 
and available total height 



Total input- 



& 



fx 



Rise 



£) 



Btu/hr 
input 



Increase 
vent 

connector 
size if 
necessary 



Tee same size as 
segment above 



Available total 
height H equals 
rise plus distance 
between tees 



Tee same 
^ size as 
segment 
above 



Other inputs 
from below 



Vent connector size 
depends on: 

• Input 

• Rise 

• Available total height H 

• Table 13.2(a) connectors 



Common vent size 
depends on: 

• Combined inputs 

• Available total height H 

• Table 13.2(a) common 
vent 



FIGURE G.l(m) Multistory Gas Vent Design Procedure for 
Each Segment of System. 



G.l.l Example 1: Single Draft Hood-Equipped Appliance. 

An installer has a 120,000-Btu/hr input appliance with a 5 in. 
diameter draft hood oudet that needs to be vented into a 10 ft 
high Type B vent system. What size vent should be used assum- 
ing (1) a 5 ft lateral single-wall metal vent connector is used 
with two 90 degree elbows or (2) a 5 ft lateral single-wall metal 
vent connector is used with three 90 degree elbows in the vent 
system? See Figure G.l.l. 

Solution 

Table 13.1(b) should be used to solve this problem, be- 
cause single-wall metal vent connectors are being used with a 
Type B vent, as follows: 

(1) Read down the first column in Table 13.1(b) until the 
row associated with a 10 ft height and 5 ft lateral is 
found. Read across this row until a vent capacity greater 
than 120,000 Btu/hr is located in the shaded columns 
labeled NAT Max for draft hood-equipped appliances. 
In this case, a 5 in. diameter vent has a capacity of 
122,000 Btu/hr and can be used for this application. 

(2) If three 90 degree elbows are used in the vent system, 
the maximum vent capacity listed in the tables must be 
reduced by 10 percent (see 13.1.3). This implies that the 
5 in. diameter vent has an adjusted capacity of only 
110,000 Btu/hr. In this case, the vent system must be 
increased to 6 in. in diameter. See the following 
calculations: 

122,000x0.90 = 110,000 for 5 in. vent 



Use individual vent for top-floor 
appliance if connector 
requirement for rise or total 
height cannot be met 

X- _ 



Listed cap 



Use vent 
connector 
table — » 



Available total 
height for top- 
floor appliance 



Rise 



Top-floor— 
appliance 



Available total 
height for third- 
floor appliance 



Use vent — 

connector 

table 

Third-floor -) 
appliance 



Rise 



Available total 
height for second- 
floor appliance 



Use available total 
height for top-floor 
appliance and 
combined input of 
all appliances on 
common vent 



^Third interconnection tee* 

Available total height 
for third-floor 
appliance and 
combined input of 

_ three appliances 
(if top-floor appliance 
is not connected, 
measure total 
height to vent top) 

_Second interconnection 
tee* 



Use available total 
_height for second-floor 
appliance and combined 
heat input of two 
appliances 



Use vent 

connector 

table 



Risel 



£X 



m 



Second-floor 
appliance -» 



First interconnection tee* 



Design vent connector for 
first-floor appliance as an 
individual vent of this total 
height for input of first- 
floor appliance 



Tee with cap optional 



3 



First-floor - 
appliance 



* Each interconnection tee is same size as 
segment of common vent directly above 



FIGURE G.l(n) Principles of Design of Multistory Vents 
Using Vent Connector and Common Vent Design Tables. 

(See 13.2.14 through 13.2.17.) 

From Table 13.2, select 6 in. vent. 

186,000x0.90 = 167,000 

This figure is greater than the required 120,000. There- 
fore, use a 6 in. vent and connector where three elbows are 
used. 

G.1.2 Example 2: Single Fan-Assisted Appliance. An installer 
has an 80,000 Btu/hr input fan-assisted appliance that must be 
installed using 10 ft of lateral connector attached to a 30 ft 
high Type B vent. Two 90 degree elbows are needed for the 
installation. Can a single-wall metal vent connector be used for 
this application? See Figure G.1.2. 

Solution 

Table 13.1(b) refers to the use of single-wall metal vent 
connectors with Type B vent. In the first column find the row 
associated with a 30 ft height and a 10 ft lateral. Read across 
this row, looking at the FAN Min and FAN Max columns, to 



2006 Edition 



ANSI Z223.1-141 



ANNEX G 



54-141 



Type B 
double-wall - 
gas vent 



Elbow 




Draft hood- 
equipped appliance 
120,000 Btu/hr input 



For SI units, 1 ft = 0.305 m. 

FIGURE G.l.l Single Draft Hood-Equipped Appliance 
Example 1. 



TypeB 
double-wall 
gas vent 

1 ft lateral — 



V 



30 ft 



O 



Vent connector 



Fan-assisted appliance 
80,000 Btu/hr input 



For SI units, 1 ft = 0.305 m. 
FIGURE G. 1 .2 Single Fan-Assisted Appliance — Example 2. 



find that a 3 in. diameter single-wall metal vent connector is 
not recommended. Moving to the next larger size single wall 
connector (4 in.), we find that a 4 in. diameter single-wall 
metal connector has a recommended minimum vent capacity 
of 91,000 Btu/hr and a recommended maximum vent capac- 
ity of 144,000 Btu/hr. The 80,000 Btu/hr fan-assisted appli- 
ance is outside this range, so the conclusion is that a single- 
wall metal vent connector cannot be used to vent this 
appliance using 10 ft of lateral for the connector. 

However, if the 80,000 Btu/hr input appliance could be 
moved to within 5 ft of the vertical vent, a 4 in. single-wall 
metal connector could be used to vent the appliance. Table 
13.1(b) shows the acceptable range of vent capacities for a 
4 in. vent with 5 ft of lateral to be between 72,000 Btu/hr and 
157,000 Btu/hr. 



If the appliance cannot be moved closer to the vertical 
vent, a Type B vent could be used as the connector material. In 
this case, Table 13.1(a) shows that, for a 30 ft high vent with 
10 ft of lateral, the acceptable range of vent capacities for a 
4 in. diameter vent attached to a fan-assisted appliance is be- 
tween 37,000 Btu/hr and 150,000 Btu/hr. 

G.1.3 Example 3: Interpolating Between Table Values. An in- 
staller has an 80,000 Btu/hr input appliance with a 4 in. diam- 
eter draft hood outlet that needs to be vented into a 12 ft high 
Type B vent. The vent connector has a 5 ft lateral length and is 
also Type B. Can this appliance be vented using a 4 in. diam- 
eter vent? 

Solution 

Table 13.1(a) is used in the case of an all Type B vent sys- 
tem. However, because there is no entry in Table 13.1 (a) for a 
height of 12 ft, interpolation must be used. Read down the 4 in. 
diameter NAT Max column to the row associated with 10 ft 
height and 5 ft lateral to find the capacity value of 77,000 Btu/hr. 
Read further down to the 15 ft height, 5 ft lateral row to find 
the capacity value of 87,000 Btu/hr. The difference between 
the 15 ft height capacity value and the 10 ft height capacity 
value is 10,000 Btu/hr. The capacity for a vent system with a 
12 ft height is equal to the capacity for a 10 ft height plus % of 
the difference between the 10 ft and 15 ft height values, or 
77,000 + % x 10,000 = 81,000 Btu/hr. Therefore, a 4 in. diam- 
eter vent can be used in the installation. 

G.2 Examples Using Common Venting Tables. 

G.2.1 Example 4: Common Venting Two Draft Hood- 
Equipped Appliances. A 35,000-Btu/hr water heater is to be 
common vented with a 150,000 Btu/hr furnace, using a com- 
mon vent with a total height of 30 ft. The connector rise is 2 ft 
for the water heater with a horizontal length of 4 ft. The con- 
nector rise for the furnace is 3 ft with a horizontal length of 
8 ft. Assume single-wall metal connectors will be used with 
Type B vent. What size connectors and combined vent should 
be used in this installation? See Figure G.2.1. 



"Fv 



30 ft 



Combined capacity 
35,000 + 150,000 = 
185,000 Btu/hr 

(— Type B double- 
wall gas vent 

Single-wall 




Draft hood- 
equipped 
water heater 
35,000 Btu/hr 
input 



Draft hood- 
equipped furnace 
150,000 Btu/hr 
input 



FIGURE G.2. 1 Common Venting Two Draft Hood-Equipped 
Appliances — Example 4. 



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ANSI Z223.1-142 



Solution 

Table 13.2(b) should be used to size single-wall metal vent 
connectors attached to Type B vertical vents. In the vent connec- 
tor capacity portion ofTable 13.2(b), find the row associated with 
a 30 ft vent height. For a 2 ft rise on the vent connector for the 
water heater, read the shaded columns for draft hood-equipped 
appliances to find that a 3 in. diameter vent connector has a 
capacity of 37,000 Btu/hr. Therefore, a 3 in. single-wall metal 
vent connector can be used with the water heater. For a draft 
hood-equipped furnace with a 3 ft rise, read across the appropri- 
ate row to find that a 5 in. diameter vent connector has a maxi- 
mum capacity of 120,000 Btu/hr (which is too small for the fur- 
nace) and a 6 in. diameter vent connector has a maximum vent 
capacity of 172,000 Btu/hr. Therefore, a 6 in. diameter vent con- 
nector should be used with the 150,000 Btu/hr furnace. Because 
both vent connector horizontal lengths are less than the maxi- 
mum lengths listed in 13.2.2, the table values can be used without 
adjustments. 

In the common vent capacity portion of Table 13.2(b), find 
the row associated with a 30 ft vent height and read over to the 
NAT + NAT portion of the 6 in. diameter column to find a 
maximum combined capacity of 257,000 Btu/hr. Since the 
two appliances total only 185,000 Btu/hr, a 6 in. common vent 
can be used. 

G.2.2 Example 5(a): Common Venting a Draft Hood- 
Equipped Water Heater with a Fan-Assisted Furnace into a 
Type B Vent. In this case, a 35,000-Btu/hr input draft hood- 
equipped water heater with a 4 in. diameter draft hood oudet, 
2 ft of connector rise, and 4 ft of horizontal length is to be 
common vented with a 100,000 Btu/hr fan-assisted furnace 
with a 4 in. diameter flue collar, 3 ft of connector rise, and 6 ft 
of horizontal length. The common vent consists of a 30 ft 
height of Type B vent. What are the recommended vent diam- 
eters for each connector and the common vent? The installer 
would like to use a single-wall metal vent connector. See Fig- 
ure G.2.2. 



Combined capacity 
35,000 + 100,000 = 
135,000 Btu/hr 



Type B 
-double-wall 
gas vent 




30 ft 



Single-wall 
connectors 



Fan-assisted furnace 
100,000 Btu/hr input 



Water heater 
35,000 Btu/hr 
input 



For SI units, 1000 Btu/hr = 0.293 kW, 1 ft = 0.305 m. 

FIGURE G.2.2 Common Venting a Draft Hood-Equipped 
Water Heater with a Fan-Assisted Furnace into a Type B 
Double-Wall Common Vent — Example 5(a). 

Solution [See Table 13.2(b).] 

Water Heater Vent Connector Diameter. Since the water heater 
vent connector horizontal length of 4 ft is less than the maxi- 
mum value listed in Table 13.2(b), the venting table values can 



be used without adjustments. Using the Vent Connector Ca- 
pacity portion of Table 13.2(b), read down the Total Vent 
Height (H) column to 30 ft and read across the 2 ft Connector 
Rise (R) row to the first Btu/hr rating in the NAT Max column 
that is equal to or greater than the water heater input rating. 
The table shows that a 3 in. vent connector has a maximum 
input rating of 37,000 Btu/hr. Although this rating is greater 
than the water heater input rating, a 3 in. vent connector is 
prohibited by 13.2.22. A 4 in. vent connector has a maximum 
input rating of 67,000 Btu/hr and is equal to the draft hood 
oudet diameter. A 4 in. vent connector is selected. Since the 
water heater is equipped with a draft hood, there are no mini- 
mum input rating restrictions. 

Furnace Vent Connector Diameter. Using the Vent Connector 
Capacity portion ofTable 13.2(b), read down the Total Vent 
Height (H) column to 30 ft and across the 3 ft Connector Rise 
(R) row. Because the furnace has a fan-assisted combustion 
system, find the first FAN Max column with a Btu/hr rating 
greater than the furnace input rating. The 4 in. vent connec- 
tor has a maximum input rating of 119,000 Btu/hr and a mini- 
mum input rating of 85,000 Btu/hr. 

The 100,000 Btu/hr furnace in this example falls within this 
range, so a 4 in. connector is adequate. Because the furnace vent 
connector horizontal length of 6 ft is less than the maximum 
value listed in 13.2.2, the venting table values can be used without 
adjustment. If the furnace had an input rating of 80,000 Btu/hr, 
a Type B vent connector [see Table 13.2(a)] would be needed in 
order to meet the minimum capacity limit. 

Common Vent Diameter. The total input to the common vent 
is 135,000 Btu/hr. Using the Common Vent Capacity portion 
ofTable 13.2 (b) , read down the Total Vent Height (H) column 
to 30 ft and across this row to find the smallest vent diameter 
in the FAN + NAT column that has a Btu/hr rating equal to or 
greater than 135,000 Btu/hr. The 4 in. common vent has a 
capacity of 132,000 Btu/hr and the 5 in. common vent has a 
capacity of 202,000 Btu/hr. Therefore, the 5 in. common vent 
should be used in this example. 

Summary. In this example, the installer can use a 4 in. diam- 
eter, single-wall metal vent connector for the water heater and a 
4 in. diameter, single-wall metal vent connector for the furnace. 
The common vent should be a 5 in. diameter Type B vent. 

G.2.3 Example 5(b): Common Venting into an Interior Ma- 
sonry Chimney. In this case, the water heater and fan-assisted 
furnace of Example 5(a) are to be common-vented into a clay- 
tile-lined masonry chimney with a 30 ft height. The chimney is 
not exposed to the outdoors below the roof line. The internal 
dimensions of the clay tile liner are nominally 8 in. x 12 in. As- 
suming the same vent connector heights, laterals, and materials 
found in Example 5 (a) , what are the recommended vent connec- 
tor diameters, and is this an acceptable installation? 

Solution 

Table 13.2(d) is used to size common venting installations 
involving single-wall connectors into masonry chimneys. 

Water Heater Vent Connector Diameter. Using Table 13.2(d), 
Vent Connector Capacity, read down the Total Vent Height 
(H) column to 30 ft, and read across the 2 ft Connector Rise 
(R) row to the first Btu/hr rating in the NAT Max column that 
is equal to or greater than the water heater input rating. The 
table shows that a 3 in. vent connector has a maximum input 
of only 31,000 Btu/hr, while a 4 in. vent connector has a maxi- 
mum input of 57,000 Btu/hr. A 4 in. vent connector must 
therefore be used. 



2006 Edition 



ANSIZ223.1-143 



ANNEX G 



54-143 



Furnace Vent Connector Diameter. Using the Vent Connector 
Capacity portion of Table 13.2(d), read down the Total Vent 
Height (H) column to 30 ft and across the 3 ft Connector Rise 
(R) row. Because the furnace has a fan-assisted combustion 
system, find the first FAN Max column with a Btu/hr rating 
greater than the furnace input rating. The 4 in. vent connec- 
tor has a maximum input rating of 127,000 Btu/hr and a mini- 
mum input rating of 95,000 Btu/hr. The 100,000 Btu/hr fur- 
nace in this example falls within this range, so a 4 in. 
connector is adequate. 

Masonry Chimney. From Table G.2.3, the Equivalent Area 
for a Nominal Liner size of 8 in. x 12 in. is 63.6 in. 2 . Using 
Table 13.2(d), Common Vent Capacity, read down the FAN + 
NAT column under the Minimum Internal Area of Chimney 
value of 63 to the row for 30 ft height to find a capacity value of 
739,000 Btu/hr. The combined input rating of the furnace 
and water heater, 135,000 Btu/hr, is less than the table value, 
so this is an acceptable installation. 

Section 13.2.16 requires the common vent area to be no 
greater than seven times the smallest listed appliance catego- 
rized vent area, flue collar area, or draft hood outlet area. 
Both appliances in this installation have 4 in. diameter outlets. 
From Table G.2.3, the equivalent area for an inside diameter 
of 4 in. is 12.2 in. 2 . Seven times 12.2 equals 85.4, which is 
greater than 63.6, so this configuration is acceptable. 

G.2.4 Example 5(c): Common Venting into an Exterior Ma- 
sonry Chimney. In this case, the water heater and fan-assisted 
furnace of Examples 5(a) and 5(b) are to be common-vented 
into an exterior masonry chimney. The chimney height, clay- 
tile-liner dimensions, and vent connector heights and laterals 
are the same as in Example 5 (b) . This system is being installed 
in Charlotte, North Carolina. Does this exterior masonry 
chimney need to be relined? If so, what corrugated metallic 
liner size is recommended? What vent connector diameters 
are recommended? See Table G.2.3 and Figure G.2.4. 

Solution 

According to 13.2.25, Type B vent connectors are required 
to be used with exterior masonry chimneys. Use Table 13.2(h) 
and Table 13.2(i) to size FAN+NAT common venting installa- 
tions involving Type-B double wall connectors into exterior 
masonry chimneys. 

The local 99 percent winter design temperature needed to 
use Table 13.2(h)and Table 13.2(i)can be found in ASHRAE 
Handbook — Fundamentals. For Charlotte, North Carolina, this 
design temperature is 19°F. 

Chimney Liner Requirement. As in Example 5(b), use the 
63 in. 2 Internal Area columns for this size clay tile liner. Read 
down the 63 in. 2 column of Table 13.2(h) to the 30 ft height 
row to find that the Combined Appliance Maximum Input is 
747,000 Btu/hr. The combined input rating of the appliances 
in this installation, 135,000 Btu/hr, is less than the maximum 
value, so this criterion is satisfied. Table 13.2(i), at a 19T De- 
sign Temperature, and at the same Vent Height and Internal 
Area used earlier, shows that the minimum allowable input 
rating of a space-heating appliance is 470,000 Btu/hr. The 
furnace input rating of 100,000 Btu/hr is less than this mini- 
mum value. So this criterion is not satisfied, and an alternative 
venting design needs to be used, such as a Type B vent shown 
in Example 5(a) or a listed chimney liner system shown in the 
remainder of the example. 

According to 13.2.19, Table 13.2(a) or Table 13.2(b) is 
used for sizing corrugated metallic liners in masonry chim- 
neys, with the maximum common vent capacities reduced by 



Table G.2.3 Masonry Chimney Liner 
Dimensions with Circular Equivalents 







Inside 






Inside 


Diameter 




Nominal 


Dimensions 


or Equivalent 


Equivalent 


Liner Size 


of Liner 


Diameter 


Area 


(in.) 


(in.) 


(in.) 


(in. 2 ) 


4x8 


VA x 6 14 


4.0 


12.2 






5.0 


19.6 






6.0 


28.3 






7.0 


38.3 


8x8 


6% x 6% 


7.4 


42.7 






8.0 


50.3 


8x12 


6M> x lOVa 


9.0 


63.6 






10.0 


78.5 


12x12 


9Vi x 9 s /4 


10.4 


83.3 






11.0 


95.0 


12x16 


9V£ x 13!/ 2 


11.8 


107.5 






12.0 


113.0 






14.0 


153.9 


16x16 


13V4 x 13V4 


14.5 


162.9 






15.0 


176.7 


16x20 


13x17 


16.2 


206.1 






18.0 


254.4 


20x20 


16VS> x 16% 


18.2 


260.2 






20.0 


314.1 


20x24 


1614- x 2OV2 


20.1 


314.2 






22.0 


380.1 


24x24 


20'/4 X 20'/4 


22.1 


380.1 






24.0 


452.3 


24x28 


20 ] /4 x 24V4 


24.1 


456.2 


28x28 


24V4 x 24V4 


26.4 


543.3 






27.0 


572.5 


30x30 


251/2 x 25 ] / 2 


27.9 


607.0 






30.0 


706.8 


30x36 


25% X 31 V2 


30.9 


749.9 






33.0 


855.3 


36x36 


3V/2X3VA 


34.4 


929.4 






36.0 


1017.9 



For SI units, 1 in. = 25.4 mm, 1 in. 2 = 645 mm 2 . 

Note: When liner sizes differ dimensionally from those shown in this 
table, equivalent diameters can be determined from published tables 
for square and rectangular ducts of equivalent carrying capacity or by 
other engineering methods. 



20 percent. This example will be continued assuming Type B 
vent connectors. 

Water Heater Vent Connector Diameter. Using Table 13.2(a), 
Vent Connector Capacity, read down the Total Vent Height 
(H) column to 30 ft, and read across the 2 ft Connector Rise 
(R) row to the first Btu/hour rating in the NAT Max column 
that is equal to or greater than the water heater input rating. 
The table shows that a 3 in. vent connector has a maximum 
capacity of 39,000 Btu/hr. Although this rating is greater than 
the water heater input rating, a 3 in. vent connector is prohib- 
ited by 13.2.20. A 4 in. vent connector has a maximum input 
rating of 70,000 Btu/hr and is equal to the draft hood outlet 
diameter. A 4 in. vent connector is selected. 

Furnace Vent Connector Diameter. Using Table 13.2(a), Vent 
Connector Capacity, read down the Total Vent Height (H) col- 
umn to 30 ft, and read across the 3 ft Connector Rise (R) row 



2006 Edition 



54-144 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-144 



-10T 
(-23°C) 




10°F 
(-23°C) 



Vi 17 ° F 

(J (-8"C) 


27° F 
(-3°C) 


37° F 
-^ (2°C) 



99% Winter Design Temperatures for the Contiguous United States 

This map is a necessarily generalized guide to temperatures in the contiguous United States. Temperatures shown for areas 
such as mountainous regions and large urban centers may not be accurate. The data used to develop this map are from the 
1 993 ASHRAE Handbook— Fundamentals (Chapter 24, Table 1 : Climate Conditions for the United States). 

For 99% winter design temperatures in Alaska, consult the ASHRAE Handbook — Fundamentals. 

99% winter design temperatures for Hawaii are greater than 37°F. 

FIGURE G.2.4 Range of Winter Design Temperatures Used in Analyzing Exterior Masonry Chimneys in the United States. 



to the first Btu/hr rating in the FAN Max column that is equal 
to or greater than the furnace input rating. The 100,000 
Btu/hr furnace in this example falls within this range, so a 

4 in. connector is adequate. 

Chimney Liner Diameter. The total input to the common vent 
is 135,000 Btu/hr. Using the Common Vent Capacity portion 
of Table 13.2(a), read down the Total Vent Height (H) column 
to 30 ft and across this row to find the smallest vent diameter 
in the FAN+NAT column that has a Btu/hr rating greater than 
135,000 Btu/hr. The 4 in. common vent has a capacity of 
138,000 Btu/hr. Reducing the maximum capacity by 20 per- 
cent (see 13.2.20) results in a maximum capacity for a 4 in. 
corrugated liner of 110,000 Btu/hr, less than the total input of 
135,000 Btu/hr. So a larger liner is needed. The 5 in. common 
vent capacity listed in Table 13.2(a) is 210,000 Btu/hr, and 
after reducing by 20 percent is 168,000 Btu/hr. Therefore, a 

5 in. corrugated metal liner should be used in this example. 

Single Wall Connectors. Once it has been established that re- 
lining the chimney is necessary, Type B double wall vent con- 
nectors are not specifically required. This example could be 
redone using Table 13.2(b) for single-wall vent connectors. 
For this case, the vent connector and liner diameters would be 
the same as found for Type B double-wall connectors. 



Annex H Recommended Procedure for Safety 
Inspection of an Existing Appliance Installation 

This annex is not a part of the requirements of this NFPA document 
but is included for informational purposes only. 

H.l General. The following procedure is intended as a guide 
to aid in determining that an appliance is properly installed 
and is in a safe condition for continuing use. 

This procedure is predicated on central furnace and boiler 
installations, and it should be recognized that generalized 
procedures cannot anticipate all situations. Accordingly, in 
some cases, deviation from this procedure is necessary to de- 
termine safe operation of the appliance. 

( 1 ) This procedure should be performed prior to any attempt 
to modify the appliance or the installation. 

(2) If it is determined a condition that could result in unsafe 
operation exists, the appliance should be shut off and the 
owner advised of the unsafe condition. 

The following steps should be followed in making the 
safety inspection: 

(1) Conduct a test for gas leakage. (See Section 8.2.) 



2006 Edition 



ANSI Z223.1-145 



ANNEX I 



54-145 



(2) Visually inspect the venting system for proper size and 
horizontal pitch, and determine that there is no block- 
age, restriction, leakage, corrosion, or other deficiencies 
that could cause an unsafe condition. 

(3) Shut off all gas to the appliance, and shut off any other 
fuel-gas burning appliance within the same room. Use 
the shutoff valve in the supply line to each appliance. 

(4) Inspect burners and crossovers for blockage and corrosion. 

(5) Applicable only to furnaces: Inspect the heat exchanger for 
cracks, openings, or excessive corrosion. 

(6) Applicable only to boilers: Inspect for evidence of water or 
combustion product leaks. 

(7) Insofar as is practical, close all building doors and win- 
dows and all doors between the space in which the 
appliance is located and other spaces of the building. 
Turn on clothes dryers. Turn on any exhaust fans, 
such as range hoods and bathroom exhausts, so they 
will operate at maximum speed. Do not operate a sum- 
mer exhaust fan. Close fireplace dampers. If, after 
completing Steps 8 through 13, it is believed sufficient 
combustion air is not available, refer to Section 9.3 of 
this code for guidance. 

(8) Place the appliance being inspected in operation. Follow 
the lighting instructions. Adjust the thermostat so the 
appliance will operate continuously. 

(9) Determine that the pilot(s), where provided, is burning 
properly and that the main burner ignition is satisfactory, 
by interrupting and re-establishing the electrical supply to 
the appliance in any convenient manner. If the appliance is 
equipped with a continuous pilot(s) , test the pilot safety 
device (s) to determine whether it is operating properly, by 
extinguishing the pilot(s) when the main burner(s) is off 
and determining, after 3 minutes, that the main burner gas 
does not flow upon a call for heat. If the appliance is not 
provided with a pilot(s), test for proper operation of the 
ignition system in accordance with the appliance manufac- 
turer's lighting and operating instructions. 

(10) Visually determine that the main burner gas is burning 
properly (i.e., no floating, lifting, or flashback). Adjust 
the primary air shutter(s) as required. If the appliance is 
equipped with high and low flame controlling or flame 
modulation, check for proper main burner operation at 
low flame. 

(11) Test for spillage at the draft hood relief opening after 
5 minutes of main burner operation. Use a flame of a 
match or candle or smoke. 

(12) Turn on all other fuel-gas-burning appliances within the 
same room so they will operate at their full inputs. Fol- 
low lighting instructions for each appliance. 

(13) Repeat Steps 10 and 11 on the appliance being in- 
spected. 

(14) Return doors, windows, exhaust fans, fireplace dampers, 
and any other fuel-gas-burning appliance to their previ- 
ous conditions of use. 

(15) Applicable only to furnaces: Check both the limit control 
and the fan control for proper operation. Limit control 
operation can be checked by blocking the circulating air 
inlet or temporarily disconnecting the electrical supply 
to the blower motor and determining that the limit con- 
trol acts to shut off the main burner gas. 

(16) Applicable only to boilers: Determine that the water pumps 
are in operating condition. Test low water cutoffs, auto- 
matic feed controls, pressure and temperature limit con- 
trols, and relief valves in accordance with the manufac- 
turer's recommendations to determine that they are in 
operating condition. 



Annex I Indoor Combustion Air 
Calculation Examples 

This annex is not a part of the requirements of this NFPA document 
but is included for informational purposes only. 

1.1 New Installation. Determine if the indoor volume is suffi- 
cient to supply combustion air for the following new installa- 
tion example. 

Example Installation 1: A 100,000 Btu/hr fan-assisted fur- 
nace and a 40,000 Btu/hr draft hood-equipped water heater 
are being installed in a basement of a new single-family home. 
The basement measures 25 ft x 40 ft with an 8 ft ceiling. 

Solution 

( 1 ) Determine the total required volume: Since the air infiltra- 
tion rate is unknown, the standard method to determine 
combustion air is used to calculate the required volume. 

(a) The combined input for the appliances located in the 
basement is calculated as follows: 

100,000 Btu/hr + 40,000 Btu/hr = 140,000 Btu/hr 

(b) The Standard Method requires that the required 
volume be determined based on 50 cubic feet per 
1000 Btu/hour. 

(c) Using Table A.9.3.2.1, the required volume for a 
140,000 Btu/hr combined input is 7,000 ft s 

(2) Determine available volume: The available volume is the 
total basement volume: 

Available Volume: 25 ft x 40 ft x 8 ft ceiling = 8,000 ft 3 

Conclusion: The installation can use indoor air because the 
available volume of 8,000 ft 3 exceeds the total required vol- 
ume of 7,000 ft 3 . No outdoor air openings are required. 

1.2 New Installation, Known Air Infiltration Rate Method. De- 
termine if the indoor volume is sufficient to supply combus- 
tion air for the following replacement installation example. 

Example Installation 2: A 100,000 Btu/hr fan-assisted fur- 
nace and a 40,000 Btu/hr draft hood-equipped water heater 
will be installed in a new single-family house. It was deter- 
mined (either by use of the ASHRAE calculation method or 
blower door test) that the house will have 0.65 air changes per 
hour. The furnace and water heater will be installed in a 20 ft 
x 35 ft basement with an 8 ft ceiling height. 

Solution 

(1) Determine the required volume: Because two types of appli- 
ances are located in the space — a fan-assisted furnace 
and a draft hood-equipped water heater — the required 
volume must be determined for each appliance and then 
combined to determine the total required volume: 

(a) Fan-assisted furnace: For structures that the air infiltra- 
tion rate is known, method 9.3.2.2 permits the use of 
the equation in 9.3.2.2(2) to determine the required 
volume for a fan-assisted appliance. Paragraph 
9.3.2.2(3) limits the use of the equation to air change 
rates equal to or less than 0.60 ACH. While the house 
was determined to have a 0.65 ACH, 0.60 is used to 
calculate the required volume. Using the equation in 
9.3.2.2(2), the required volume for a 100,000 Btu/hr 
fan-assisted furnace is calculated as follows: 



2006 Edition 



54-146 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-146 



15 ft V 100,000 Btu/hr 



0.65 [ 1,000 Btu/hr 
= 2,308 ft 3 



Paragraph 9.3.2.2 specifies a lower required volume 
limitation for fan-assisted appliances at no smaller than 
25 ft 3 per 1,000 Btu/hr. From Table A.9.3.2.2(b), the 
lower limit is 

2,500 ft 3 

Because the calculated required volume of 2,308 ft 3 
falls below the lower required volume limit, the lower 
limit of 2,500 ft 3 must be used as the minimum required 
volume, 
(b) Draft-hood equipped water heater: For structures for which 
the air infiltration rate is known, method 9.3.2.2 permits 
the use of the equation in 9.3.2.2(1) to determine the 
required volume for a draft hood-equipped appliance. 
Paragraph 9.3.2.2(3) limits the use of the equation to air 
change rates equal to or less than 0.60 ACH. While the 
house was determined to have a 0.65 ACH, 0.60 is used 
to calculate the required volume. Using the equation in 
9.3.2.2(1), the required volume for the 40,000 Btu/hr 
water heater is calculated as follows: 



21 ft 3 (40,000 Btu/hr 



(c) 



0.60 i, 1,000 Btu/hr 



= 1,400 ft 3 

Paragraph 9.3.2.2 specifies a lower required volume 
limitation for appliances other than fan-assisted at no 
smaller than 35 ft 3 per 1,000 Btu/hr. From Table 
A.9.3.2.2(a), the lower limit is 

1,400 ft 3 

Because the calculated required volume of 1 ,292 ft 3 
falls below the lower required volume limit, the lower 
limit of 1,400 ft 3 must be used as the minimum required 
volume. 

Total required volume: Section 9.3.2 states that the total 
required volume of indoor air is the sum of the required 
volumes for all appliances located in the space: 

Total Required = 2,500 ft 3 + 1,400 ft 3 = 3,900 ft 3 

(2) Determine available volume: The available volume is deter- 
mined as follows: 

(20 ft x 35 ft) x 8 ft = 5, 600 ft 3 

Conclusion: The installation can use indoor air because 
the available volume of 5,600 ft 3 exceeds the total re- 
quired volume of 3,900 ft 3 . No outdoor air openings are 
required. 

1.3 New Installation, Known Air Infiltration Rate Method. De- 
termine if the indoor volume is sufficient to supply combus- 
tion air for the following replacement installation example. 

Example Installation 3: A 100,000 Btu/hr fan-assisted furnace 
and a 40,000 Btu/hr draft hood-equipped water heater will be 
installed in a new single-family house. It was determined (either 
by use of the ASHRAE calculation method or blower door test) 
that the house will have 0.30 air changes per hour. The furnace 
and water heater will be installed in a 20 ft x 35 ft basement with 
an 8 ft ceiling height. 



Solution 

(1) Determine the required volume: Because two types of appli- 
ances are located in the space — a fan-assisted furnace 
and a draft hood-equipped water heater — the required 
volume must be determined for each appliance and then 
combined to determine the total required volume: 
(a) Fan-assisted furnace: For structures that the air infiltra- 
tion rate is known, method 9.3.2.2 permits the use of 
the equation in 9.3.2.2(2) to determine the required 
volume for a fan-assisted appliance. Paragraph 9.3.2.3 
limits the use of the equation to air change rates 
equal to or less than 0.60 ACH. Because 0.30 ACH is 
less than 0.60 ACH, 0.30 can be used to calculate the 
required volume. Using the equation in 9.3.2.2(2), 
the required volume for a 100,000 Btu/hr fan-assisted 
furnace is calculated as follows: 



15 ft 3 



0.30 



100,000 Btu/hr ^ 
1,000 Btu/hr 



= 5,000 ft 3 

Paragraph 9.3.2.2 specifies a lower required volume 
limitation for fan-assisted appliances at no smaller than 
25 ft 3 per 1,000 Btu/hr. From Table A.9.3.2.2(b), the 
lower limit is 

2,500 ft 3 

Because the calculated required volume of 5,000 ft 3 is 
above the lower required volume limit, use this amount 
as the minimum required volume. 

(b) Draft hood-equipped water heater: For structures that the 
air infiltration rate is known, method 9.3.2.2 permits 
the use of the equation in 9.3.2.2(1) to determine the 
required volume for a draft hood-equipped appli- 
ance. Paragraph 9.3.2.2(3) limits the use of the equa- 
tion to air change rates equal to or less than 0.60 
ACH. While the house was determined to have a 0.65 
ACH, 0.30 ACH is used to calculate the required vol- 
ume. Using the equation in 9.3.2.2(1), the required 
volume for the 40,000 Btu/hr water heater is calcu- 
lated as follows: 

21 ft 3 ("40,000 Btu/hr 



(c) 



0.30 { 1,000 Btu/hr 
= 2,800 ft 3 



Paragraph 9.3.2.2 specifies a lower required volume 
limitation for appliances other than fan-assisted at no 
smaller than 35 ft 3 per 1,000 Btu/hr. From Table 
A.9.3.2.2(a), the lower limit is 

1,400 ft 3 

Because the calculated required volume of 2,800 ft 3 is 
above the lower required volume limit, use this amount 
as the minimum required volume. 

Total required volume: Section 9.3.2 states that the total 
required volume to use indoor air is the sum of the 
required volumes for all appliances located in the 
space: 

Total Required = 5,000 ft 3 + 2,800 ft 3 = 7,800 ft 3 



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ANSIZ223.1-147 



ANNEX K 



54-147 



(2) Determine available volume: The available volume is deter- 
mined as follows: 

(20 ft x 35 ft) x 8 ft = 5, 600 ft 3 

Conclusion: The installation cannot use indoor air alone, be- 
cause the available volume of 5,600 ft 3 is less than the total 
required volume of 7,800 ft 3 . Outdoor air openings can be 
sized in accordance with all air from the outdoors (see 9.3.3) 
or by use of the combination of indoor/outdoor air method 
(see 9.3.4). 



140,000 Btu/hr 
3,000 Btu/in. 2 



= 47 in. 5 



(6) Determine the minimum outdoor combustion air open- 
ing area: 

Outdoor opening area = 0.49 (from Step 4) x 47 in. 2 = 23 in. 2 

Paragraph 9.3.4(3) (c) requires the minimum dimension of 
the air opening should not be less than 3 in. 



Annex J Example of Combination of Indoor and 
Outdoor Combustion and Ventilation Opening Design 

This annex is not a part of the requirements of this NFPA document 
but is included for informational purposes only. 

J.l Example of Combination Indoor and Outdoor Combus- 
tion Air Opening Design. Determine the required combina- 
tion of indoor and outdoor combustion air opening sizes for 
the following appliance installation example. 

Example Installation: A fan-assisted furnace and a draft 
hood-equipped water heater with the following inputs are lo- 
cated in a 15 ft x 30 ft basement with an 8 ft ceiling. No addi- 
tional indoor spaces can be used to help meet the appliance 
combustion air needs. 

Fan-Assisted Furnace Input: 100,000 Btu/hr 

Draft Hood-Equipped Water Heater Input: 40,000 Btu/hr 

Solution 

( 1 ) Determine the total available room volume: 
Appliance room volume: 

15 ft x 30 ft with an 8 ft ceiling = 3600 ft 3 

(2) Determine the total required volume: The standard method to 
determine combustion air will be used to calculate the 
required volume. 

The combined input for the appliances located in the 
basement is calculated as follows: 

100,000 Btu/hr + 40,000 Btu/hr = 140,000 Btu/hr 

The Standard Method requires that the required volume 
be determined based on 50 cubic feet per 1000 Btu/hour. 
Using Table A.9. 3.2.1, the required volume for a 140,000 
Btu/hr water heater is 

7,000 ft 3 

Conclusion: The indoor volume is insufficient to supply 
combustion air since the total of 3600 ft 3 does not meet 
the required volume of 7000 ft 3 . Therefore, additional 
combustion air must be provided from the outdoors. 

(3) Determine ratio of the available volume to the required 
volume: 



3600 ft 3 
7000 ft 3 



= 0.51 



(4) Determine the reduction factor to be used to reduce the 
full outdoor air opening size to the minimum required 
based on ratio of indoor spaces: 

1.00 - 0.51 (from Step 3) = 0.49 

(5) Determine the single outdoor combustion air opening 
size as though all combustion air is to come from out- 
doors. In this example, the combustion air opening di- 
rectly communicates with the outdoors: 



Annex K Other Useful Definitions 

This annex is not apart of the requirements of this NFPA document 
but is included for informational purposes only. 

K.1 Useful Terms. The following terms are not used in the 
code. They are used in appliance standards and by manufac- 
turers of products covered by the code. 

K.1.1 Ambient Temperature. The temperature of the sur- 
rounding medium; usually used to refer to the temperature of 
the air in which a structure is situated or a device operates. 

K. 1.2 Automatic Damper Regulator. A mechanically or electri- 
cally actuated device designed to maintain a constant draft on 
combustion appliances. 

K.1.3 Burner, Induced-Draft. A burner that depends on draft 
induced by a fan that is an integral part of the appliance and is 
located downstream from the burner. 

K.1.4 Burner, Injection (Atmospheric). A burner in which the 
air at atmospheric pressure is injected into the burner by a jet 
of gas. 

K.1. 5 Burner, Power, Premixing. A power burner in which all 
or nearly all of the air for combustion is mixed with the gas as 
primary air. 

K.1. 6 Conversion Burner, Gas, Firing Door Type. A conversion 
burner specifically for boiler or furnace firing door installation. 

K.1.7 Conversion Burner, Gas, Inshot Type. A conversion 
burner normally for boiler or furnace ash pit installation and 
fired in a horizontal position. 

K.1. 8 Conversion Burner, Gas, Upshot Type. A conversion 
burner normally for boiler or furnace ash pit installation and 
fired in a vertical position at approximately grate level. 

K.1. 9 Decorative Appliance for Installation in a Vented Fire- 
place, Coal Basket. An open-flame-type appliance consisting 
of a metal basket that is filled with simulated coals and gives 
the appearance of a coal fire when in operation. 

K.1. 10 Decorative Appliance for Installation in a Vented Fire- 
place, Fireplace Insert. Consists of an open-flame, radiant-type 
appliance mounted in a decorative metal panel to cover the 
fireplace or mantel opening and having provisions for venting 
into the fireplace chimney. 

K.1. 11 Decorative Appliance for Installation in a Vented Fire- 
place, Gas Log. An open-flame-type appliance consisting of a 
metal frame or base supporting simulated logs. 

K.1. 12 Decorative Appliance for Installation in a Vented Fire- 
place, Radiant Appliance. An open-front appliance designed 
primarily to convert the energy in fuel gas to radiant heat by 
means of refractory radiants or similar radiating materials. 



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ANSIZ223.1-148 



K.1.13 Fireplace, Factory-Built. Afireplace composed of listed 
factory-built components assembled in accordance with the 
manufacturer's installation instructions to form the com- 
pleted fireplace. 

K. 1. 14 Fireplace, Masonry. A hearth and fire chamber of solid 
masonry units such as bricks, stones, listed masonry units, or 
reinforced concrete, provided with a suitable chimney. 

K. 1 . 1 5 Floor Furnace, Fan-Type. Afloor furnace equipped with 
a fan that provides the primary means for circulation of air. 

K.1.16 Floor Furnace, Gravity-Type. A floor furnace depend- 
ing primarily on circulation of air by gravity. This classification 
also includes floor furnaces equipped with booster-type fans 
that do not materially restrict free circulation of air by gravity 
flow when such fans are not in operation. 

K. 1 . 1 7 Furnace, Direct Vent Central. A system consisting of ( 1 ) a 
central furnace for indoor installation, (2) combustion air con- 
nections between the central furnace and the outdoor atmo- 
sphere, (3) flue-gas connections between the central furnace and 
the vent cap, and (4) a vent cap for installation outdoors, sup- 
plied by the manufacturer and constructed so that all air for com- 
bustion is obtained from the outdoor atmosphere and all flue 
gases are discharged to the outdoor atmosphere. 

K.1.18 Furnace, Downflow. Afurnace designed with airflow dis- 
charge vertically downward at or near the bottom of the furnace. 

K. 1 . 1 9 Furnace, Forced Air, with Cooling Unit. A single-package 
unit, consisting of a gas-fired, forced-air furnace of the down- 
flow, horizontal, or upflow type combined with an electrically 
or gas-operated summer air-conditioning system, contained in 
a common casing. 

K.1.20 Furnace, Gravity. A furnace depending primarily on 
circulation of air by gravity. 

K. 1 .2 1 Furnace, Gravity, with Booster Fan. A furnace equipped 
with a booster fan that does not materially restrict free circula- 
tion of air by gravity flow when the fan is not in operation. 

K.1.22 Furnace, Gravity, with Integral Fan. Afurnace equipped 
with a fan or blower as an integral part of its construction and 
operable on gravity systems only. The fan or blower is used 
only to overcome the internal furnace resistance to airflow. 

K1.23 Furnace, Horizontal. Afurnace designed for low head- 
room installation with airflow across the heating element es- 
sentially in a horizontal path. 

K.1.24 Furnace, Upflow. A furnace designed with airflow dis- 
charge vertically upward at or near the top of the furnace. This 
classification includes "highboy" furnaces with the blower 
mounted below the heating element and "lowboy" furnaces 
with the blower mounted beside the heating element. 

K.1.25 Gas Main or Distribution Main. A pipe installed in a 
community to convey gas to individual services or other mains. 

K.1.26 Household Cooking Appliance, Floor-Supported Unit. 

A self-contained cooking appliance for installation directly on 
the floor. It has a top section and an oven section. It may have 
additional sections. 

K.1.27 Indirect Oven. An oven in which the flue gases do not 
flow through the oven compartment. 

K 1 .28 Joint, Adhesive. Ajoint made in plastic piping by the use 
of an adhesive substance that forms a continuous bond between 
the mating surfaces without dissolving either one of them. 



K.1.29 Joint, Solvent Cement. Ajoint made in thermoplastic 
piping by the use of a solvent or solvent cement that forms a 
continuous bond between the mating surfaces. 

K.1.30 Leak Detector. An instrument for determining con- 
centration of gas in air. 

K.1.31 Loads, Connected. Sum of the rated Btu/hr gas input 
to individual appliances connected to a piping system. May 
also be expressed in cubic feet per hour. 

K.1.32 Orifice Cap (Hood). A movable fitting having an ori- 
fice that permits adjustment of the flow of gas by the changing 
of its position with respect to a fixed needle or other device. 

K.1.33 Orifice Spud. A removable plug or cap containing an 
orifice that permits adjustment of the flow of gas either by 
substitution of a spud with a different sized orifice or by the 
motion of a needle with respect to it. 

K.1.34 Pressure Control. Manual or automatic maintenance 
of pressure, in all or part of a system, at a predetermined level, 
or within a selected range. 

K.1.35 Regulator, Appliance, Adjustable. (1) Spring type, lim- 
ited adjustment: a regulator in which the regulating force act- 
ing upon the diaphragm is derived principally from a spring, 
the loading of which is adjustable over a range of not more 
than ±15 percent of the outlet pressure at the midpoint of the 
adjustment range; (2) spring type, standard adjustment: a 
regulator in which the regulating force acting on the dia- 
phragm is derived principally from a spring, the loading of 
which is adjustable. 

K.1.36 Regulator, Appliance, Multistage. A regulator for use 
with a single gas whose adjustment means can be positioned 
manually or automatically to two or more predetermined out- 
let pressure settings. 

K.1.37 Regulator, Appliance, Nonadjustable. (1) Spring type, 
nonadjustable: a regulator in which the regulating force act- 
ing on the diaphragm is derived principally from a spring, the 
loading of which is not field adjustable; (2) weight type: a 
regulator in which the regulating force acting upon the dia- 
phragm is derived from a weight or combination of weights. 

K.1.38 Room Heater, Unvented Circulator. A room heater de- 
signed to convert the energy in fuel gas to convected and radi- 
ant heat by direct mixing of air to be heated with the combus- 
tion products and excess air inside the jacket. 

K.1.39 Room Heater, Vented. A vented, self-contained, free- 
standing, nonrecessed, fuel-gas-burning appliance for furnish- 
ing warm air to the space in which installed, directly from the 
heater without duct connections. 

K.1.40 Room Heater, Vented Circulator. A room heater de- 
signed to convert the energy in fuel gas to convected and radi- 
ant heat, by transfer of heat from flue gases to a heat ex- 
changer surface, without mixing of flue gases with circulating 
heated air. 

K.1.41 Room Heater, Vented Circulator, Fan Type. A vented 
circulator equipped with an integral circulating air fan, the 
operation of which is necessary for satisfactory appliance per- 
formance. 

K.1.42 Room Heater, Vented Overhead Heater. A room heater 
designed for suspension from or attachment to or adjacent to 
the ceiling of the room being heated and transferring the en- 
ergy of the fuel gas to the space being heated primarily by 



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ANSIZ223.1-149 



ANNEX L 



54-149 



radiation downward from a hot surface, and in which there is 
no mixing of flue gases with the air of the space being heated. 

K.1.43 Room Heater, Wall Heater, Unvented Closed Front. 

An unvented circulator having a closed front, for insertion in 
or attachment to a wall or partition. 

K.1.44 Valve, Automatic Gas Shutoff. Avalve used in conjunc- 
tion with an automatic gas shutoff device to shut off the gas 
supply to a fuel-gas-burning water heating system. 

K.1.45 Valve, Individual Main Burner. Avalve that controls 
the gas supply to an individual main burner. 

K.1.46 Valve, Main Burner Control. Avalve that controls the 
gas supply to the main burner manifold. 

K.1.47 Valve, Manual Main Gas Control. A manually operated 
valve in the gas line for the purpose of completely turning on 
or shutting off the gas supply to the appliance, except to a 
pilot or pilots that are provided with independent shutoff. 

K.1.48 Vented Wall Furnace, Fan-Type. A wall furnace that is 
equipped with a fan. 

K.1.49 Vented Wall Furnace, Gravity-Type. A wall furnace that 
depends on circulation of air by gravity. 

K.1.50 Venting System, Mechanical Draft, Induced. A portion 
of a venting system using a fan or other mechanical means to 
cause the removal of flue or vent gases under nonpositive 
static vent pressure. 

K.1.51 Venting System, Mechanical Draft, Power. See 

3.3.98. 7.1, Forced Mechanical Draft Venting System. 

K.1.52 Water Heater, Automatic Circulating Tank. A water 
heater that furnishes hot water to be stored in a separate ves- 
sel. Storage tank temperatures are controlled by means of a 
thermostat installed on the water heater. Circulation can be 
either gravity or forced. 

K.1.53 Water Heater, Automatic Instantaneous. A water heater 
that has a rated input of at least 4000 Btu/hr/gal (5 kW/L) of 
self-stored water. Automatic control is obtained by water- 
actuated control, thermostatic control, or a combination of 
water-actuated control and thermostatic control. This classifi- 
cation includes faucet-type water heaters designed to deliver 
water through a single faucet integral with or directly adjacent 
to the appliance. 

K.1.54 Water Heater, Coil Circulation. A water heater whose 
heat transfer surface is composed primarily of water tubes less 
than V/i in. (38 mm) in internal diameter and that requires 
circulation. 

K.1.55 Water Heater, Commercial Storage. A water heater that 
heats and stores water at a thermostatically controlled tem- 
perature for delivery on demand. Input rating: 75,000 Btu/hr 
(21,980 W) or more. 

K.1.56 Water Heater, Countertop Domestic Storage. (1) Con- 
cealed type: a vented automatic storage heater that is designed 
for flush installation beneath a countertop 36 in. (910 mm) 
high, wherein the entire heater is concealed; (2) flush type: a 
vented automatic storage water heater that has flat sides, top, 
front, and back and is designed primarily for flush installation 
in conjunction with or adjacent to a counter 36 in. (910 mm) 
high, wherein the front and top of the heater casing are ex- 
posed; and (3) recessed type: a vented automatic storage water 
heater that has flat sides, top, front, and back and is designed 



for flush installation beneath a counter 36 in. (910 mm) high, 
wherein the front of the heater casing is exposed. 

K.1.57 Water Heater, Domestic Storage. A water heater that 
heats and stores water at a thermostatically controlled tem- 
perature for delivery on demand. Input rating may not exceed 
75,000 Btu/hr (21,980 W). 

K.1.58 Water Heater, Nonautomatic Circulating Tank. A wa- 
ter heater that furnishes hot water to be stored in a separate 
vessel. Storage tank temperatures are controlled by means of a 
thermostat installed in the storage vessel. 



Annex L Informational References 

L.l Referenced Publications. The documents or portions 
thereof listed in this annex are referenced within the informa- 
tional sections of this code and are not part of the require- 
ments of this document unless also listed in Chapter 2 for 
other reasons. 

L.l.l NFPA Publications. National Fire Protection Associa- 
tion, 1 Batterymarch Park, Quincy, MA 021 69-7471. 

NFPA30, Flammable and Combustible Liquids Code, 2003 edition. 

NFPA 59, Utility LP-Gas Plant Code, 2004 edition. 

NFPA59A, Standard for the Production, Storage, and Handling 
of Liquefied Natural Gas (LNG), 2006 edition. 

NFPA 61, Standard for the Prevention of Fires and Dust Explo- 
sions in Agricultural and Food Processing Facilities, 2002 edition. 

NFPA 68, Guide for Venting of Deflagrations, 2002 edition. 

NFPA 70, National Electrical Code®, 2005 edition. 

NFPA 86, Standard for Ovens and Furnaces, 2003 edition. 

NFPA90A, Standard for the Installation of Air-Conditioning and 
Ventilating Systems, 2002 edition. 

NFPA 90B, Standard for the Installation of Warm Air Heating 
and Air-Conditioning Systems, 2006 edition. 

NFPA 96, Standard for Ventilation Control and Fire Protection of 
Commercial Cooking Operations, 2004 edition. 

NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid 
Fuel-Burning Appliances, 2003 edition. 

NFPA501A, Standard for Fire Safety Criteria for Manufactured 
Home Installations, Sites, and Communities, 2005 edition. 

L.1.2 Other Publications. 

L.l. 2.1 API Publication. American Petroleum Institute, 1220 
L Street, NW, Washington, DC 20005-4070. 

API 1104, Standard for Welding Pipelines and Related Facilities, 
1999. 

L.l. 2.2 ASHRAE Publications. American Society of Heating, 
Refrigerating and Air-Conditioning Engineers, Inc., 1791 
Tullie Circle, N.E., Atlanta, GA 30329-2305, (404)636-8400, 
www.ashrae.org. 

ASHRAE Handbook — Fundamentals, 1997. 

ASHRAE Handbook — HVAC Systems and Equipment, 1999. 

L. 1.2.3 ASME Publication. American Society of Mechanical 
Engineers, Three Park Avenue, New York, NY 10016-5990, 
(800)843-2763, www.asme.org. 

ASME Boiler and Pressure Vessel Code, Section DC and Section IV, 
1998. 



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54-150 



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ANSIZ223.1-150 



L.l.2.4 ASTM Publications. American Society for Testing and 
Materials, 100 Barr Harbor Drive, West Conshohocken, PA 
19428-2959, (610)833-9585, www.astm.org. 

ANSI/ ASTM D 2385, Method of Test for Hydrogen Sulfide and 
Mercaptan Sulfur in Natural Gas (Cadmium Sulfate — Iodometric 
Titration Method), 1981. 

ANSI/ ASTM D 2420, Method of Test for Hydrogen Sulfide in 
Liquefied Petroleum (LP) Gases (Lead Acetate Method), 1991 (Reaf- 
firmed 1996). 

L.l.2.5 AWS Publications. American Welding Society, 550 N.W. 
Lejeune Road, Miami, FL 33126, (800)443-9353, www.aws.org. 

AWS B2.1, Standard for Welding Procedure and Performance 
Qualification, 1998. 

AWS B2.2, Standard for Brazing Procedure and Performance 
Qualification, 1991. 

L. 1.2.6 CSA International Publications. CSA-America, Inc., 
8501 East Pleasant Valley Road, Cleveland, OH 44131, 
(216)524-4990, www.csa-america.org. 

AGA/CGA NGV 1, Compressed Natural Gas Vehicle (NGV) Fu- 
eling Connection Devices, 1999. 

AGA/CGA NGV 3.1, Fuel System Components for Natural Gas 
Powered Vehicles, 1999. 

ANSI/IAS LC 2A, Agricultural Heaters, 1998. 

ANSI Z21.1, Household Cooking Gas Appliances, 2000. 

ANSI Z21.5.1/CSA7.1, Gas Clothes Dryers — Volume I— Type 1 
Clothes Dryers, 1999. 

ANSI Z21.5.2/CSA7.2, Gas Clothes Dryers — Volume II— Type 2 
Clothes Dryers, 2001. 

ANSI Z21.10.1/CSA 4.1, Gas Water Heaters — Volume I — 
Storage, Water Heaters with Input Ratings of 75, 000 Btu per Hour en- 
Less, 2001. 

ANSI Z21.10.3/CSA 4.3, Gas Water Heaters — Volume III — 
Storage, Water with Input Ratings above 75,000 Btu per Hour, Cir- 
culating and Instantaneous, 2001 . 

ANSI Z2 1.1 1.1, Gas-Fired Room Heaters — Volume I — Vented 
Room Heaters, 1991. (Included in Z21.86/ CSA 2.32, 2000.) 

ANSI Z21.11.2, Gas-Fired Room Heaters — Volumell — Unvented 
Room Heaters, 2000. 

ANSI Z21.12, Draft Hoods, 1990 (Reaffirmed 2000). 

ANSI Z21.13/CSA 4.9, Gas-Fired Low-Pressure Steam and Hot 
Water Boilers, 2000 (Reaffirmed 1998). 

ANSI Z21.15/CGA9.1, Manually Operated Gas Valves for Ap- 
pliances, Appliance Connector Valves, and Hose End Valves, 1997. 

ANSI Z21.17/CSA2.7, Domestic Gas Conversion Burners, 1998. 

ANSI Z21.18/CSA6.3, Gas Appliance Pressure Regulators, 2000. 

ANSI Z21.19/CSA 1.4, Refrigerators Using Gas Fuel, 2002 (Re- 
affirmed 1999). 

ANSI Z21.20, Automatic Gas Ignition Systems and Components, 
2000. 

ANSI Z21.21/CGA6.5, Automatic Valves for Gas Appliances, 
2000. 

ANSI Z21 .22/CSA 4.4, Relief Valves and Automatic Gas Shutoff 
Devices for Hot Water Supply Systems, 1999 (Reaffirmed 1998). 

ANSI Z21.23, Gas Appliance Thermostats, 2000 (Reaffirmed 
1998). 

ANSI Z21.24/CSA 6.10, Metal Connectors for Gas Appliances, 
2001. 

ANSI Z21.35/CGA6.8, Pilot Gas Filters, 1995. 



ANSI Z21.40.1/CGA 2.91-M96, Gas-Fired Absorption Summer 
Air Conditioning Appliances, 1996. 

ANSI Z21.40.2/CGA 2.92, Gas-Fired Work Activated Air- 
Conditioning and Heat Pump Appliances (Internal Combustion), 1996. 

ANSI Z21.40.4/CGA 2.94, Performance Testing and Rating of 
Gas Fired, Air-Conditioning and Heat Pump Appliances, 1 996. 

ANSI Z2 1.42, Gas-Fired Illuminating Appliances, 1993 (Reaf- 
firmed 1998). 

ANSI Z21.47/CSA2.3, Gas-Fired Central Furnaces, 2001. 

ANSI Z21.50/CSA2.22, Vented Gas Fireplaces, 2000. 

ANSI Z21.54/CSA8.4, Gas Hose Connectors for Portable Out- 
door Gas-Fired Appliances, 1996. 

ANSI Z21.56/CSA4.7, Gas-Fired Pool Heaters, 2001. 

ANSI Z21.57, Recreational Vehicle Cooking Gas Appliances, 2001 
(Reaffirmed 1998). 

ANSI Z21.58/CGA 1.6, Outdoor Cooking Gas Appliances, 1995 
(Reaffirmed 2001). 

ANSI Z21.60/CGA2.26, Decorative Gas Appliances for Instal- 
lation in Solid-Fuel Burning Fireplaces, 1996. 

ANSI Z21.61, Gas-Fired Toilets, 1983 (Reaffirmed 1996). 

ANSI Z21.66/CGA 6.14, Automatic Vent Damper Devices for 
Use with Gas-Fired Appliances, 1996. 

ANSI Z21.69/CSA 6.16, Connectors for Movable Gas Appli- 
ances, 1997 (Reaffirmed 2001) . 

ANSI Z21.71, Automatic Intermittent Pilot Ignition Systems for 
Field Installations, 1993 (Reaffirmed 1998). 

ANSI Z21.77/CGA 6.23, Manually-Operated Piezo-Electric 
Spark Gas Ignition Systems and Components, 1995. 

ANSI Z21.78/CGA6.20, Combination Gas Controls for Gas Ap- 
pliances, 2000. 

ANSI Z21.83, Fuel Cell Power Plants, 1998. 

ANSI Z21.84, Manually Lighted, Natural Gas, Decorative Gas 
Appliances for Installation in Solid-Fuel Burning Appliances, 1999. 

ANSI Z21. 86/ CSA 2.32, Vented Gas-Fired Space Heating Equip- 
ment, 2000. 

ANSI Z21.87/CSA4.6, Automatic Gas Shutoff Devices for Hot 
Water Supply Systems, 1999. 

ANSI Z21.88/CSA2.33, Vented Gas-Fireplace Heaters, 2000. 

ANSI Z21.91, Ventless Firebox Enclosures for Gas-Fired Unvented 
Decorative Room Heaters, 2001. 

ANSI Z83.3, Gas Utilization Equipment in Large Boilers, 1971 
(Reaffirmed 1995). 

ANSI Z83.4/CSA 3.7, Direct Gas-Fired Make-Up Air Heaters, 
1999 (Reaffirmed 1998). 

ANSI Z83.6, Gas-Fired Infrared Heaters, 1990 (Reaffirmed 
1998). 

ANSI Z83.8/CGA2.6, Gas Fired Duct Furnaces and UnitHeat- 
ers, 1996. 

ANSI Z83.il/CGA 1.8, Food Service Equipment, 1996. 

ANSI Z21.90, Gas Convenience Outlets and Optional Enclo- 
sures, 2003. 

IAS U.S. 7, Requirements for Gas Convenience Outlets and Op- 
tional Enclosures, 1990. 

IAS U.S. 9, Requirements for Gas-Fired, Desiccant Type Dehu- 
midifiers and Central Air Conditioners, 1990. 

IAS U.S. 42, Requirement for Gas Fired Commercial Dishwashers, 
1992. 

IAS NGV2, Basic Requirements for Compressed Natural Gas Ve- 
hicle (NGV) Containers, 1998. 



2006 Edition 



ANSIZ223.1-151 



ANNEX L 



54-151 



L.l.2.7 MSS Publications. Manufacturers Standardization So- 
ciety of the Valve and Fittings Industry, 5203 Leesburg Pike, 
Suite 502, Falls Church, VA 22041. 

MSS SP-6, Standard Finishes for Contact Faces of Pipe Flanges 
and Connecting-End Flanges of Valves and Fittings, 1999. 

ANSI/MSS SP-58, Pipe Hangers and Supports — Materials, 
Design and Manufacture, 1993. 

L.l.2.8 NACE Publication. National Association of Corrosion 
Engineers, 1440 South Creek Drive, Houston, TX 77084-4906. 
NACE RP 0169, Control of External Corrosion on Underground 
or Submerged Metallic Piping Systems, 1996. 

L.l.2.9 UL Publications. Underwriters Laboratories Inc., 333 
Pfingsten Road, Northbrook, IL 60062-2096. 

UL 103, Chimneys, Factory-Built, Residential Type and Building 
Heating Appliances, 1995. 

ANSI/UL 441, Gas Vents, 1996. 



ANSI/UL 641, Low-Temperature Venting Systems, 1995. 
UL 65 1 , Schedule 40 and Schedule 80 Rigid PVC Conduit, 2004. 
UL1738, Venting Systems for Gas Burning Appliances, Categories 
II, III and TV, 1993. 

UL 1777, Chimney Liners, 1996. 

L. 1.2. 10 U.S. Government Publication. U.S. Government Print- 
ing Office, Washington, DC 20402. 

Manufactured Home Construction and Safety Standard, Tide 24, 
Code of Federal Regulations, Part 3280. 

L.l.2.11 Other Publication. 

Piping Handbook, 2000, New York: McGraw-Hill Book Com- 
pany. 

L.2 Informational References. (Reserved) 

L.3 References for Extracts in Informational Sections. (Re- 
served) 



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Index 

© 2005 National Fire Protection Association. All Rights Reserved. 

The copyright in this index is separate and distinct from the copyright in the document that it indexes. The licensing provisions set forth for the 
document are not applicable to this index. This index may not be reproduced in whole or in part by any means without the express written 
permission of NFPA. 



-A- 

Aboveground piping 7.2, A. 7.2.5 

Access doors and pane|s 

Duct furnaces 10.10.3 

Floor furnaces 10.11.8 

Wall heaters 10.27.1.5 

Accessible 

Appliances 9.2.1 

In attics 9.5.1 

On roofs 9.4.3 

Definition 3.3.1 

Readily (definition) 3.3.1.1 

Valves 7.9.2.1 

Adoption of code A.1.5 

Agency, qualified 4.1 

Definition 3.3.83 

Air 

Circulating 10.7.3, 10.10.5, 10.11.3, 10.26.3, 10.27.3 

Definition 3.3.2.1 

Ducts 12.3.5 

Combustion see Combustion air 

Dilution see Dilution air 

Excess (definition) 3.3.2.3 

Make-up see Make-up air 

Primary see Primary air 

Process 9.1.7 

Use under pressure 9.1.5 

Air conditioning 

Appliances 10.2, A.10.2.6 

Definition 3.3.3 

Aircraft hangars 

Duct furnaces in 10.10.7 

Heaters in 9.1.12, 10.18.4, 10.26.5 

Air ducts see Ducts 

Air shutter (definition) 3.3.4 

Altitude, high 11.1.2,13.1.5, 13.2.11, Table F.l(d), Annex F 

Ambient temperature (definition) K.1.1 

Anchors, pipe 7.2.6 

Anodeless risers 5.6.4.3 

Definition 3.3.5 

Appliance categorized vent diameter/area (definition) 3.3.7 

Appliances see also Equipment 

Air for combustion and ventilation see Combustion air; 

Ventilation 

Approval 9.1.1, A.9.1.1, A.9.1.6 

Attics, in 9.5, 12.11.2.4(1) 

Automatically controlled (definition) 3.3.6.1 

Carpeting, installation on 9.2.3 

Categorized vent diameter 

Area see Vent(s) , Sizes 

Clearance to combustible materials 9.2.2 

Combination units 9.1.21 

Chimneys 12.6.5.3, 12.6.5.4, A.12.6.5.3 

Venting Table 12.5.1 

Connections to building piping 9.6, A.9.6.6 

Convenience oudets 9.6.6, A.9.6.6 

Converted 9.1.2,9.1.3 

Coordination of design, construction, and 

maintenance Annex B 

Counter (gas) see Food service appliances 

Decorative see Decorative appliances 

Definition 3.3.6 



Direct vent see Direct vent appliances 

Electrical systems 9.7 

Extra devices or attachments 9.1.15 

Fan-assisted combustion 

Definition 3.3.6.4 

Venting system G.1.2 

Food service see Food service appliances 

Household cooking see Household cooking appliances 

Illuminating 10.16, Table 10.16.2.2 

Installation of Chap. 9 

Instructions 

Installation 9.1 .22 

Operating 11.7 

Leakage test 8.2, A.8.2.3 

Louvers, grilles, and screens 9.3.7 

Low-heat see subhead: Nonresidential low-heat 

Medium-heat see subhead: Nonresidential medium-heat 

Mobile, connections 9.6.3 

Nonresidential low-heat 12.6.2.1, Table 12.8.4.4, 12.11.2.5, 

12.11.14.2(3) 

Definition 3.3.6.8 

Nonresidential medium-heat ... 12.6.2.2, Table 12.8.4.4, 12.11.14.3 

Definition 3.3.6.9 

Operation procedures Chap. 1 1 

Outdoor 

Cooking appliances 10.20 

Definition 3.3.6.10 

Protection of 9.1.23 

Piping 

Capacity of 9.1.16 

Strain on 9.1.17 

Placing in operation 8.3.4 

Portable, connections 9.6.3 

Pressure regulators 5.8.5.2, 9.1.18, 9.1.19 

Protection see Protection 

Purging 8.3.4 

On roofs 9.4 

Type of gas(es) 9.1.3 

Vented see Vented appliances; Venting; Venting systems 

In well-ventilated spaces 12.3.4 

Applicability of code 1.1.1 

Approved (definition) 3.2.1, A.3.2.1 

Atmospheric pressure (definition) 3.3.79. 1 

Attics, appliances in 9.5, 12.11.2.4(1) 

Authority having jurisdiction (definition) 3.2.2, A.3.2.2 

Automatically operated vent dampers 12.15 

Automatic damper regulator (definition) K.1.2 

Automatic firechecks 7.12.1 (3), 7.12.6, A.7.12.6(l) 

Definition 3.3.8 

Automatic gas shutoff devices 10.28.5 

Definition 3.3.28.1 

Automatic ignition see Ignition 

Automatic valves (definition) 3.3.103.2 



Backfilling 7.1.2.3 

Backfire preventers see Safety blowouts 

Back pressure 

Definition 3.3.79.2 

Protection 5.10 

Baffle (definition) 3.3.10 



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54-153 



Barometric draft regulators 9.3.1.4, 12.13.4 to 10.12.6, A.12. 13.4 

Definition 3.3.86.2.1 

Bathroom, installation in 10.1 .2, A.10. 1.2 

Bedroom, installation in 10.1 .2, A.10.1.2 

Bends 

Pipe 7.5 

Vent connectors 12.11.6 

Bleeds 

Diaphragm-type valves 9.1.20 

Industrial air heaters 10.8.6, 10.9.6 

Blowers, mixing see Mixing blowers 

Boilers 

Central heating 10.3, A.10.3.6, A.10.3.7.3 

Assembly and installation 10.3.3 

Clearance Table 10.2.3(a), Table 10.2.3(b), 10.3.2 

Cooling units used with 10.3.9 

Low water cutoff 10.3.5, 11.5 

Steam safety and pressure relief valves 10.3.6, A.10.3.6 

Temperature- or pressure-limiting devices 10.3.4 

Hot water heating (definition) 3.3.11.1 

Hot water supply (definition) 3.3.11.2 

Low-pressure (definition) 3.3.11.3 

Steam (definition) 3.3.11.4 

Bonding, electrical 7. 1 3 

Branch lines 7.2.3, 7.4.1, 7.8 

Branch length pipe sizing method 6.1.2, A.6. 1.2, C.4.2, 

C.8.3, C.8.4 

Definition 3.3. 1 2 

Breeching see Vent connectors 

Broilers 

Definition 3.3.14 

Household cooking appliance 

Definition 3.3.6.7.1 

Protection above 10.19.3 

Unit 

Commercial 10.19.4 

Definition 3.3.14.1 

Domestic, protection above 10. 19.3 

Open-top 10.19 

Btu A.5.4.2 

Definition 3.3.15 

Buildings 
Piping in 

Building structure for 7.2.2 

Concealed 7.3 

Connection of appliances and equipment to 9.6, A.9.6.6 

Prohibited locations 7.2.5, A.7.2.5 

Piping under 7.1.6 

Structural members 9.1.8 

Built-in household cooking units 10.15.2 

Definition 3.3.6.7.2 

Burners see also Conversion burners, gas 

Combination gas and oil burners 

Chimneys for 12.6.5.4 

Venting system Table 12.5.1 

Definition 3.3. 16 

Forced draft see subhead: Power 

Gas conversion see Conversion burners, gas 

Induced-draft (definition) K.1.3 

Injection (atmospheric) (definition) K. 1 .4 

Injection (Bunsen) type (definition) 3.3.16.3 

Input adjustment 11.1, All. 1.1 

Power 

Definition 3.3.16.5 

Fan-assisted (definition) 3.3.16.5.1 

Premixing (definition) K.1.5 

Primary air adjustment 11.2, A.11.2 

In residential garages 9.1.10.1 

Bypass piping 5.8.6 

Bypass valves 

Gas line pressure regulators 5.8.6 

Pool heaters 10.21.4 



-c- 

Capping, of outlets 7.7.2 

Carpeting, installation of appliances on 9.2.3 

Casters, for floor-mounted food service appliances 10.12.6 

Central furnaces see Furnaces 

Central premix system 7.12, A. 7.12.4 to A.7.12.6(l) 

Definition 3.3.98.1 

Chases, vertical, piping in 7.4, A.7.4.3 

Chimneys 12.6, A.12.6.1.3, A.12.6.5.3 

Checking draft 1 1 .6, A. 11 .6 

Cleanouts 12.6.4.3, 12.6.7 

Definition 3.3.17 

Exterior masonry Tables 13.2(f) to (i), G.2.4 

Definition 3.3.17.1 

Factory-built 12.6.1.1, 12.6.2.4, 12.6.6, 12.6.8.2, 12.11.2.6(4) 

Definition 3.3.17.2 

Masonry 12.6.1.3, 12.6.8.1, 12.6.8.2, 12.7.1(4), 13.1.7, 

13.2.20, A.12.6.1.3, A.13.1.7,A.13.2.20, G.2.3 

Definition 3.3.17.3 

Metal 12.6.1.2,12.6.8.2 

Definition 3.3.17.4 

Obstructions 12.16, 13.1.1 

Vent connectors 12.11.2.5, 12.11.2.6, 12.11.3.3, 12.11.11 

Venting system 13.1.7, 13.1.11, 13.2.20, 13.2.21, Table 13.2(c), 

Table 13.2(d), Tables 13.2(f) to (h), A.13.1.7, A.13.2.20, 
G.2.3 

Circuits, electrical 7.14, 9.7.3 

Circulating air see Air, Circulating 

Clearances 9.2.2 

Air-conditioning equipment, indoor installation 10.2.3 

Boilers, central heating ....Table 10.2.3(a), Table 10.2.3(b), 10.3.2 

Clothes dryers 10.4.1 

Draft hoods 12.13.7 

Food service appliances 

Counter appliances 10.13.1 to 10.13.3 

Floor-mounted 10.12.1, 10.12.2 

Outdoor cooking appliances 10.20.2 

Furnaces 

Central 10.3.2 

Duct 10.10.1 

Floor 10.11.7 

Gas-fired toilets 10.25.1 

Heaters 

Industrial air 10.8.4, 10.9.4 

Infrared 10.18.2 

Pool 10.21.2 

Room 10.23.3 

Unit 10.26.2 

Water 10.28.2 

Illuminating appliances 10.16.1, 10.16.2, Table 10.16.2.2 

Refrigerators, gas 10.22.1 

Single-wall metal pipe for vents 12.8.4.4 

Vent connectors 12.11.5 

Clothes dryers 

Definition 3.3.18 

Installation 10.4 

Multiple family or public use 10.4.5.6, 10.4.6 

Type 1 10.4.1(1), 10.4.2, 10.4.4, 12.3.2(4) 

Definition 3.3.18.1 

Type 2 10.4.1(2), 10.4.2, 10.4.5 

Definition 3.3.18.2 

Venting, 9.3.1.5, 10.4.2 to 10.4.5, 12.3.2(4) 

Coal basket see Decorative appliances, to install in 

vented fireplaces 
Combustible material 

Clearances to see Clearances 

Definition 3.3.65.1 

Food service appliances mounted on/adjacent to 10.12.3, 

10.12.5, 10.13.4, 10.14 

Roofs, metal pipe passing through 12.8.4.5 

Combustion (definition) 3.3.19 



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ANSIZ223.1-154 



Combustion air 9.1 .2(1) , 9.3, A.9.3 

Combination indoor and outdoor 9.3.4, Annex J 

Ducts 9.3.8 

Engineered installations 9.3.5 

Floor furnaces 10.11.3 

Gas fireplaces, vented 10.7.3 

Indoor 9.3.2, Table A.9.3.2.1, Tables 9.3.2.2(a) and (b), 

Fig.A.9.3.2.3(l) 

Calculauon examples Annex I, Annex J 

Infrared heaters 10.18.3 

Mechanical supply 9.3.6 

Outdoor 9.3.3, Figs. A.9.3.3.1(l) (a) and (b), 

Fig.A.9.3.3.1(2), Fig. A.9.3.3.2 

Calculauon examples Annex J 

Unit heaters 10.26.3 

Wall heaters ....'. 10.27.3 

Combustion chamber (definition) 3.3.20 

Combustion products (definition) 3.3.21 

Commercial cooking appliances see Food service appliances 

Common vent 12.7.4,12.11.3.5,12.11.3.6, 13.2.4 to 13.2.10, 

• Fig. G.l(k), Fig. G.l(l), G.2, Fig. G.2.1, Fig. G.2.2 
Definition 3.3.105.1 

Common vent manifolds see Manifolds 

Compressed natural gas (CNG) vehicular fuel systems 1 0.29 

Concealed gas piping 

In buildings 7.3 

Definition 3.3.77.1 

Condensate (condensation) 

Definition 3.3.22 

Drain 12.10 

Connections 

Air conditioners 10.2.2 

Chimney 12.11.11 

Electrical 7.15,9.7.1 

Equipment and appliances 9.6, A.9.6.6 

Gas 5.13.2 

Branch 7.4.1, 7.8 

Concealed piping 7.3.2 

Plastic and metallic piping 7.1.7.1, 7.1.7.2 

Portable and mobile industrial appliances 9.6.3 

Connectors 

Gas hose, to appliances and equipment 9.6.2 

Vent see Vent connectors 

Construction 

Chase 7.4.2 

Checklist B.2 

Coordination B. 1 

Overpressure protection devices 5.9.3 

Single-wall metal pipe 12.8.1 

Consumption (definition) 3.3.23 

Control piping 

Definition 3.3.77.2 

Overpressure protection devices 5.9.4 

Controls 

Definition 3.3.24 

Draft 12.13, 12.16, A.12.13.4 

Duct furnaces 10.10.4 

As obstructions 12.16 

Protective devices 11.5 

Safety shutoff devices see Safety shutoff devices 

Convenience outlets see Gas convenience outlets 

Conversion burners, gas 10.5 

Definition 3.3.16.1 

Firing door type (definition) K. 1 .6 

Inshot type (definition) K 1 .7 

Upshot type (definition) K.1.8 

Cooking appliances see Food service appliances; Household 

cooking appliances 

Cooling units; see also Refrigeration systems 

Boilers, used with 10.3.9 

Furnaces, used with 10.3.8 



Corrosion, protection against .... 5.6.2.4, 5.6.2.5,5.6.3.3,5.6.6, 7.1.3, 
7.3.5.1, 7.3.5.2, 12.6.1.3, A.7.1.3, A.12.6.1.3 

Counter appliances, gas see Food service appliances 

CSST piping systems 7.2.8, 9.6.1 (5) 

Cubic feet (cu ft.) of gas 5.4.2.1 

Definition 3.3.25 

-D- 

Dampers 

Automatically operated vent 12.15 

Chimney, free opening area of Table 10.6.2.3 

Gravity 10.8.7.2, 10.9.7.2 

Manually operated 12.14 

Obstructions and 13.1.1 

Outside 10.8.5, 10.9.5 

Decorative appliances, to install in vented fireplaces 10.6, 

Table 10.6.2.3, Table 12.5.1, A.10.6.1 

Coal basket (definition) K.1.9 

Definition 3.3.6.2 

Fireplace insert (definition) K.1.10 

Gas log (definition) K.1.11 

Radiant appliance (definition) K.1.12 

Deep fat fryer see Food service appliances 

Defects, detection of 5.6.5, 8.1.5 

Definitions Chap. 3, Annex K. 

Design 

Checklist B.2 

Coordination B.l 

Design certification (definition) 3.3.27 

Design pressure 

Allowable pressure drop 5.4.1, 5.4.4, A.5. 4.1, C.7(4) 

Definition 3.3.79.3 

Maximum 5.5.1, A5.5. 1 ( 1 ) 

Detectors, leak see Leak detectors 

Devices see also Quick-disconnect devices; Safety shutoff devices; 

Vent damper device, automatic 

Automatic gas shutoff devices 10.28.5 

Definition 3.3.28.1 

Dilution air 9.3.1.1 to 9.3.1.3, 9.3.5, 9.3.7.1 

Definition 3.3.2.2 

Direct gas-fired industrial air heaters 

Air supply 10.8.5, 10.9.5 

Nonrecirculating 10.8 

Definition 3.3.55.1 

Prohibited installations 10.9.2, A.10.9.2.2 

Recirculating 10.9, A.10.9.2.2 

Definition 3.3.55.2 

Venting of 12.7.2(1) (c), 12.7.2(c) 

In well-ventilated spaces 12.3.4 

Direct gas-fired makeup air heaters, venting of 12.3.2(9) 

Direct vent appliances 

Definition 3.3.6.3 

Venting of 12.3.5, Table 12.5.1, 12.7.2(1) (d), 

12.9.1 Ex. 1, 12.9.3 

Direct vent central furnaces (definition) K.1.17 

Distribution mains or gas mains (definition) K, 1 .25 

Diversity factor (definition) 3.3.29 

Domestic laundry stoves 10.14 

Definition 3.3.30 

Venting 12.3.2(3) 

Draft(s) 9.8.2 

Checking 11.6.A.11.6 

Definition 3.3.31 

Mechanical 12.4.3, 12.7.2(l)(f), 12.9.1, 12.9.2, 12.11.4.2 

Definition 3.3.31.1 

Natural (definition) 3.3.31.2 

Requirements 12.4.1 

Draft controls 12.13, 12.16, A.12.13.4 

Draft hoods 9.3.1.4, 10.10.4, 11.6, 12.13, A.11.6, A.12.13.4 

Chimneys 12.6.1.3 Ex., 12.6.2.3, 12.6.3.1 

Conversion accessories 13.1.10, 13.2.23 



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INDEX 



54-155 



Definition 3.3.32 

Vent connectors Table 12.8.4.4 

Vents and venting systems Table 12.5.1, 12.7.3.1, 12.8.5(1), 

12.11.2.2, 12.11.2.3, 12.11.3, 13.1.2, 13.1.4, 13.1.10, 
13.1.11(3), 13.2.12, 13.2.13, 13.2.18, 13.2.22(2), 13.2.23, 
13.2.24, Table 13.2(e), A.12.7.3.1,A.12.8.5(1),A.12.11. 3, 
Annex G 

Draft regulators 12.16; see also Barometric draft regulators 

Definition 3.3.86.2 

Drain, condensation 12.10 

Drip liquids 4.3.2.1 

Drips 7.2.3, 7.6 

Definition 3.3.33 

Dry gas 7.2.3, 7.2.4 

Definition 3.3.34 

Duct furnaces 10.10 

In commercial garages and aircraft hangars 10.10.7 

Definition 3.3.46.3 

Use with refrigeration systems 10.10.6 

Ducts 

Air 9.3.8, 10.2.3(6), 10.3.7, 10.27.3, 12.4.5, A.10.3.7.3 

Exhaust 10.4.4, 10.4.5 

Unit heaters 10.26.4 

-E- 

Effective ground-fault current path (definition) 3.3.35 

Elbows 7.5.3, 13.1.3, 13.2.6, 13.2.7 

Electrical systems 7.13 to 7.15 

Air conditioning equipment 10.2.7 

Gas utilization equipment 9.7 

Ignition and control devices 9.7.2 

Enforcement of code 1.5, A.1.5 

Engines, stationary gas 10.24 

Equipment see also Appliances 

Added or converted 9.1.2, 9.1.3 

Approval 9.1.1, A.9.1.1, A.9.1.6 

Bleed lines for diaphragm-type valves 9.1 .20 

Combination 9.1 .21 

Connections to building piping 9.6, A.9.6.6 

Coordination of design, construction, and 

maintenance Annex B 

Definition 3.3.36 

Installation Chap. 9 

Instructions 

Installation 9.1.22 

Operating 11.7 

Leakage test 8.2, A.8.2.3 

Outdoor, protection of 9.1.23 

Placing in operation 8.3.4 

Equipment shutoff valves see Valves 

Equivalency to code 1.4 

Excess air (definition) 3.3.2.3 

Exhaust systems, mechanical see Mechanical exhaust systems 

Explosion heads (soft heads or rupture discs) 7.12.6(4) 

Definition 3.3.37 

Exterior masonry chimneys see Chimneys 



Fan-assisted combustion system 13.2.23, 13.2.24 

Definition 3.3.98.2 

Venting system 12.11.3.1, G.1.2 

E4N+FAN 13.2.1(3), Tables 13.2(a) to (d) 

Definition 3.3.40 

IAN Max 13.1.6, Tables 13.1(a) to (d), 13.2.3(1), 13.2.19, 

Tables 13.2(a) to (d) 

Definition 3.3.38 

EANMin 13.1.1(2), 13.1.6, Tables 13.1(a) to (d), 13.2.1(3), 

13.2.3(2), 13.2.19, Tables 13.2(a) to (d) 

Definition 3.3.39 

FAN+NAT 13.2.1(2), 13.2.1(3), 13.2.22(3), 13.2.22(4), 

Tables 13.2(a) to (d), Table 13.2(h) 
Definition 3.3.41 



Firechecks see Automatic firechecks 

Fireplace insert see Decorative appliances, to install in vented 

fireplaces 

Fireplaces see also Decorative appliances, to install in vented 

fireplaces 

Definition 3.3.42 

Factory-built (definition) K.1.13 

Gas see Gas fireplaces 

Make-up air 9.3.1.5 

Masonry (definition) K.1.14 

Oudets, capping 7.7.2.2 

Vent connectors 12.11.13 

Fireplace screens 10.6.3 

Fittings 

Appliance and equipment connections 9.5.1(2), 9.6.1(1) 

Concealed piping 7.3.2 

Corrosion, protection against 5.6.6, 7.1.3, 7.3.5.2, A.7.1.3 

Gas pipe turns 7.5 

Metallic 5.6.8, A.5.6.8.1 

Overpressure relief device 5.9.8 

Plastic 5.6.4, 5.6.9, A.5.6.4.2 

Used 5.6.1.2 

Workmanship and defects 5.6.5 

Flame arresters 7.12.2(2) 

Definition 3.3.43 

Flammable liquids, handling of 4.3.2 

Flammable vapors, appliances in area of 9.1.9 

Flange gaskets 5.6.11 

Flanges 5.6.10 

Floor furnaces 10.11 

Definition 3.3.46.5 

Fan-type (definition) K.1.15 

First floor installation 10.11. 12 

Gravity-type (definition) K.1.16 

Upper floor installation 10.11.11 

Floor-mounted equipment 

Foodservice 10.12, A.10.12.8 

Household cooking appliances 10.15.1 

Floor-supported unit (definition) K.1.26 

Unit heaters 10.26.2.2 

Floors, piping in 7.3.5, 12.11.14 

Flowmeters 7.12.2(1 ) 

Flues 

Appliance (definition) 3.3.44.1 

Chimney (definition) 3.3.44.2 

Flue collars 12.6.2.3, 12.11.3.6, 13.1.2, 13.1.4, 13.1.9, 13.2.13, 

13.2.18, 13.2.24 

Definition 3.3.45 

Multiple, on single appliance 12.11.3.2 

Flue gases 

Definition 3.3.50.1 

Venting of 9.1 . 14 

Food service appliances see also Broilers; Household cooking 

appliances 

Combustible material adjacent to cooking top 10.12.5 

Connections, moving of appliance and 9.6.1 .1 

Counter appliances 10.13 

Definition 3.3.6.5.2 

Deep fat fryers (definition) 3.3.6.5.3 

Floor-mounted 10. 12, A.10. 1 2.8 

Gas-fired kettle (definition) 3.3.6.5.7 

Oven, baking and roasting (definition) 3.3.6.5.1 

Range 12.3.2(1) 

Definition 3.3.6.5.4 

Steam cooker (definition) 3.3.6.5.5 

Steam generator (definition) 3.3.6.5.6 

Venting 12.3.2(1) to (3), 12.3.2(7) 

Forced-air furnaces see Furnaces 

Foundations, piping through 7. 1 .5 

Freezing, protection against 7.1.4, 7.2.3, A.7. 1.4 

Fuel cell power plants 10.31 



2006 Edition 



54-156 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-156 



Furnace plenums 10.2.3(5), 10.2.3(6), 10.2.5, 10.3.2.6, 10.3.7, 

12.4.5, A.10.3.7.3 

Definition 3.3.47 

Furnaces 

Central Table 10.2.3(a), Table 10.2.3(b), 10.3, A.10.3.6, 

A.10.3.7.3 

Definition 3.3.46.1 

Direct vent central (definition) K.1. 17 

Downflow (definition) K.1 .18 

Duct see Duct furnaces 

Enclosed (definition) 3.3.46.4 

Floor see Floor furnaces 

Forced-air 

With cooling unit 10.3.8(1 ) 

Definition K. 1.19 

Definition 3.3.46.6 

Gravity 

With booster fan K.1.21 

Definition K1.20 

With integral fan K.1.22 

Horizontal (definition) K.1.23 

Refrigeration coils and 10.3.8 

Upflow (definition) K1.24 

Wall see Wall furnaces 

-G- 

Garages 

Commercial 

Appliances in 9.1.11 

Duct furnaces in 10.10.7 

Heaters in 9.1.11.2, 10.18.4, 10.26.5 

Repair 

Appliances in 9.1.11.2 

Definition 3.3.48.1 

Residential 

Appliances in 9.1.10 

Definition 3.3.48.2 

Gas-air mixtures 

Flammable 7.12, A.7.12.4 to A.7.12.6(l) 

Outside the flammable range 7.11 

Gas appliances see Appliances 

Gas convenience outlets 7.7.1.6, 9.6.6, A.9.6.6 

Definition 3.3.49 

Gases 

Definition 3.3.50 

Dry see Dry gas 

Flow of, through fixed orifices Annex F 

Flue 

Definidon 3.3.50.1 

Venting of 9.1.14 

LP-Gas systems see LP-Gas systems 

Maximum demand 5.4.1, 5.4.2, A.5.4.1, A.5.4.2 

Purged, discharge of 8.3.3 

Used in appliances 9.1.3 

Utility (definition) 3.3.50.2 

Vent (definition) 3.3.50.3 

Gas-fired air conditioners 10.2, A.10.2.6 

Definition 3.3.51 

Gas-fired heat pumps 10.2, A.10.2.6 

Definition 3.3.52 

Gas fireplaces see also Decorative appliances, to install in vented 

fireplaces 

Direct vent (definition) 3.3.42.1.1 

Vented 10.7, A.10.7.1 

Definition 3.3.42.1.2 

Gaskets, flange 5.6.11 

Gas log see Decorative appliances, to install in vented fireplaces 

Gas mains (definition) K.1. 25 

Gas-mixing machines 7.11, 7.12.1(1), 7.12.3 

Definition 3.3.53 

Installation 7.12.5, A.7.12.5.1, A.7.12.5.4 



Gas range (definition) 3.3.6.5.4 

Gas reliefs 10.8.6, 10.9.6 

Gas supplier regulations 1 .1.2 

Gas utilization equipment see Equipment 

Gas vents 12.7, A.12.7.3.1 

Checking draft 11.6, A.11.6 

Definition 3.3.105.2 

Integral, appliances with 12.3.6 

Integral, equipment with Table 12.5.1, 12.7.2(1) (e) 

Multistory design Fig. G.l(m), Fig. G.l(n) 

Serving equipment on more than one floor 12.7.4 

Spaces surrounding 12.6.8 

Special type 12.3.3, 12.6.8 

Definition 3.3.105.2.1 

TypeB Table 12.5.1, 12.6.1.3 Ex., 12.6.3.1, 12.7.2(2), 12.7.4.3, 

Table 12.8.4.4, 12.11.2.4(1) (a), 12.11.14.2(1), 13.1.11, 
13.2.22 

Definition 3.3.105.2.2 

Type B-W Table 12.5.1, 12.7.1(2), 12.7.2(3) 

Definition 3.3.105.2.3 

TypeL ....Table 12.5.1, 12.7.2(2), Table 12.8.4.4, 12.11.2.4(1) (a) 

Definition 3.3.105.2.4 

Wall heaters 10.27.1.3, 10.27.1.4 

Governor, zero 7.12.4, A.7.12.4 

Definition 3.3. 1 10 

Gravity see Specific gravity 

Gravity furnaces see Furnaces 

Grilles 

Protecting openings 9.3.7.1 

Wall heaters 10.27.1.5 

Grounding, electrical 7.13 

-H- 

Hangars sec Aircraft hangars 

Hangers, pipe 7.2.6 

Health care occupancy (definition) 3.3.71.1 

Heaters see also Direct gas-fired industrial air heaters; Direct 

gas-fired makeup air heaters; Infrared heaters; Pool 
heaters; Room heaters; Unit heaters; Water heaters 

In aircraft hangars 9.1.12, 10.18.4, 10.26.5 

In commercial garages 9.1.11.2, 10.18.4, 10.26.5 

Heating value (total) (definition) 3.3.56 

Heat pumps see Gas-fired heat pumps 

Heat reclaimers 12.16 

High altitude sec Altitude, high 

Hoods 

Draft see Draft hoods 

Duct furnaces 10.10.4 

Ventilating see Ventilating hoods 

Hoop stress (definition) 3.3.97.1 

Hot plates 

Commercial counter appliances 10.13 

Definition 3.3.6.5.2 

Domestic 10.14 

Definition 3.3.57.1 

Venting 12.3.2(3) 

Hot taps (definition) 3.3.58 

Household cooking appliances 10.15 

Broilers 

Definition 3.3.6.7.1 

Protection above 10.19.3 

Built-in units 10.15.2 

Definition 3.3.6.7.2 

Definition 3.3.6.7 

Floor-mounted 10.15.1 

Floor-supported unit (definition) K.1. 26 

Outdoor 10.20 

Definition 3.3.6.10 

Hybrid pressure system 

Definition 3.3.98.3 

Pipe sizing 6.1.3, C.4.3, C.8.2 



2006 Edition 



ANSI Z223.1-157 



INDEX 



54-157 



-I- 

Identification 

Gas pressure regulators 5.8.7 

Meters, gas 5.7.5 

Ignition 

Accidental, prevention of 4.3 

Automatic 11.4 

Definition 3.3.59.1 

Electrical 9.7.2 

Sources 4.3.1 

Definition 3.3.59.2 

Illuminating appliances 10.16, Table 10.16.2.2 

Incinerators 

Commercial-industrial 10.17 

Draft regulators, barometric 12.13.4, A.12.13.4 

Vent connectors 12.11.2.6 

Venting 12.4.3.2 Ex., Table 12.5.1, 12.6.3.2 

Indirect ovens (definition) K 1 .27 

Induced-draft burners (definition) Kl .3 

Industrial air heaters see Direct gas-fired industrial air heaters 

Infrared heaters 10.18 

Definition 3.3.55.3 

Injection (atmospheric/Bunsen) burners (definition) ... 3.3.16.3, K.1.4 
Inspections 

Chimneys 12.6.4 

Draft 11.6.A.11.6 

Existing installation Annex H 

Gas piping 8.1, A.8.1.4.3 

Ignition, automatic 11.4 

Protective devices 11 .5 

Safety shutoff devices 11.3 

Vent connectors 12.11.12 

Installations 

Appliances, equipment, and accessories Chap. 9 

Chimneys 12.6.1, 12.6.2, A.12.6.1.3 

Draft hoods and draft controls 12.13.2, 12.13.3 

Electrical 9.7 

Gas piping Chap. 7 

Overpressure protection devices 5.9.3 

Roofs, appliances on 9.4.2 

Single-wall metal pipe for vents 12.8.4 

Specific equipment Chap. 10 

Instructions 

Appliance and equipment installation 9. 1 .22 

Manufacturers 1.1.2 

Operating 11.7 

Insulating millboard (definition) 3.3.60 

Interruption of service 4.2 

Interruption of work 4.2.2 

J- 

Joining methods 5.6, A.5.6.2.3 to A.5.6.8.1 

Joint compounds, thread see Thread joint compounds 

Joints 

Adhesive (definition) K.1.28 

Concealed piping 7.3.2 

Corrosion, protection against 7.1.3, A.7. 1.3 

Flared 5.6.8.3 

Metallic 5.6.8, A.5.6.8.1 

Plastic 5.6.9,7.5.2(2) 

Solvent cement (definition) K.1. 29 

Tubing 5.6.8.2 

Vent connectors 12.11.7 

-K- 

Kettle, gas-fired see Food service appliances 

-L- 

Labeled (definition) 3.2.3 

Laundry stoves see Domestic laundry stoves 



Leakage 

Emergency procedure for Annex E 

Pressure test 8.1.5 

System, appliance, and equipment test 8.2, A. 8. 2. 3 

Leak check 

Definition 3.3.62 

Suggested method Annex D 

Leak detectors 8.1.5 

Definition K.1.30 

Limit controls 11.5; see <z£so Temperature limit controls/devices 

Definition 3.3.24.1 

Listed (definition) 3.2.4, A.3.2.4 

Loads, connected (definition) K.1. 31 

Longest length pipe sizing method 6.1.1, A.6.1.1, C.4.1, C.8.1 

Louvers 

Heaters 10.8.5, 10.8.7.2 

Industrial air heaters 10.9.5, 10.9.7.2 

Protecting openings 9.3.7.1, 9.3.7.3 

LP-Gas systems 5.5.2,5.6.7.4,9.1.4 

Fixed orifices, flow of gas through Table F.l (b) 

High pressure gas formula Table 6.4.2 

Leakage check D.3(2) 

Pipe sizing tables Tables 6.2(a) to (m), 6.3, C.3.3 

Plastic pipe, use of 5.6.9(4) 

-M- 

Main burners (definition) 3.3.16.4 

Maintenance B.3 

Make-up air 9.3.1.5, 10.4.3; see also Direct gas-fired makeup air 

heaters 

Manifold 

Common vent 9.1.19(6), 9.1.20(5), 13.2.4 

Manifolds 

Common vent 

Definition 3.3.63.1 

Gas (definition) 3.3.63.2 

Manual reset valves see Valves, Manual reset 

Manufactured homes 

Appliances for 10.30 

Definition 3.3.64 

Manufacturer's instructions 1.1.2 

Marking 

Gas vents 12.7.6 

Single-wall metallic pipe 12.8.7 

Masonry chimneys see Chimneys 

Material see Combustible material; Noncombustible material 

Maximum working pressure 

Definition 3.3.79.4 

Overpressure relief device and 5.9.5 

Mechanical exhaust systems 9.3.1.5,9.3.6, 12.4.4, 12.7.2(1) (g), 

A.12.4.4 

Clothes dryers 10.4.2, 10.4.4, 10.4.5 

Definition 3.3.98.4 

Mechanical venting systems see Venting systems 

Metallic pipe 5.6.2, A.5.6.2.3; see also Tubing 

Appliance and equipment connections 9.5.1(1), 9.5.1(2) 

Connection to plastic piping 7.1.7.2 

Corrosion, protection against 5.6.2.4, 5.6.2.5, 5.6.3.3, 

5.6.6, 7.3.5.1, 7.3.5.2 

Joints and fittings 5.6.8, A.5.6.8.1 

Low pressure gas pipe sizing tables C.3.2 

Single-wall, for venting 12.8, Table 12.8.4.4, 13.2.25, 

Table 13.2(e), A.12.8.2, A.12.8.5(l) 

Sizing Tables 6.2(a) to (q), Tables 6.3(a) to (j), Table C.6(a) 

Threads 5.6.2.4,5.6.7 

Turns 7.5. 1 

Meter (definition) 3.3.66 

Meters, gas 5.7, A.5.7 



2006 Edition 



54-158 



NATIONAL FUEL GAS CODE 



ANSIZ223.1-158 



Mixing blowers 7.12.3, 7.12.4, 7.12.5.3, A.7.12.4 

Definition 3.3.67 

Multistory installations 13.2.14 to 13.2.17 

-N- 
NA 13.1.1(2), 13.2.1(3) 

Definition 3.3.68 

NAT Max 13.1.1(1), 13.1.6, Tables 13.1(a) to (d), 13.2.1(1), 

13.2.3(1), 13.2.19, Tables 13.2(a) to (d) 

Definition 3.3.69 

NAT+NAT ... 13.2.1(2), 13.2.22(3), 13.2.22(4), Tables 13.2(a) to (d), 
Table 13.2(f), Tables 13.2(g), Table 13.2(i) 

Definition 3.3.70 

Natural draft venting systems (definition) 3.3.98.5 

Noncombustible material 10.2.4 

Definition 3.3.65.2 

Thimbles 12.8.4.5 

Nondisplaceable valve member (definition) 3.3.104.1 

Notification of interrupted service 4.2.1 

-o- 

Occupancy 

Health care (definition) 3.3.71.1 

Residential board and care (definition) 3.3.71.2 

Offset, vent 13.2.5 

Definition 3.3.107 

Openings see also Relief openings 

Chimneys 12.6.5.2 

Combination indoor and outdoor combustion air ... 9.3.4, Annex J 

Indoor combustion air 9.3.2.3, Fig. A.9.3.2.3(l) 

Outdoor combustion air 9.3.3, Fig. A.9.3.3.2 

Pipe, size of 5.9.8 

Operation of appliances, procedures Chap. 1 1 

Orifice cap (hood) 

Definition K. 1 .32 

Orifices 

Definition 3.3.72 

Fixed, flow of gas through Annex F 

Orifice spud (definition) K. 1 .33 

Outdoor cooking appliances 10.20 

Definition 3.3.6.10 

Outlets 

Convenience see Gas convenience outlets 

Piping 7.7 

Outside, installation of piping . . . 7.2.1; see also Underground piping 

Ovens 

Baking and roasting see Food service appliances 

Indirect (definition) K. 1 .27 

Overpressure protection devices 5.9 

Piping in vertical chases 7.4.1 

Setting 5.9.5 

Unauthorized operation 5.9.6 

Oxygen 

As test medium 8.1.2 

Use under pressure 9.1.5 

-P- 

Parking structures 

Appliances in 9.1 .1 1 .1 

Basement or underground (definition) 3.3.74.1 

Definition 3.3.74 

Enclosed (definition) 3.3.74.2 

Partitions 

Piping in 7.3.3 

Tubing in 7.3.4 

PUot (definition) 3.3.75 

Pipes and piping see also Piping systems, gas 

Aboveground 7.2, A.7.2.5 

Bends 7.5 

Branch see Branch lines 

Buildings, in see Buildings, Piping in 



Bypass 5.8.6 

Clearances, underground piping 7.1.1 

Concealed 

In buildings 7.3 

Definition 3.3.77.1 

Connections see Connections; Connectors 

Control see Control piping 

Defects 5.6.5,8.1.5 

Definition 3.3.76, 3.3.77 

Drips 7.6 

Equivalent length (definition) 3.3.76.1 

Floors, in 7.3.5 

Hangers and anchors 7.2.6 

Identification, multiple meter installations 5.7.5 

Independent 10.2.1 

Inspection, testing, and purging Chap. 8 

Installation 5.1.1, Chap. 7, 9.6.8 

Joining methods 5.6, A.5.6.2.3 toA.5.6.8.1 

Materials 5.6, A.5.6.2.3 to A.5.6.8.1 

Metallic see Metallic pipe 

Outlets 7.7 

Partitions, in 7.3.3, 7.3.4 

Plastic see Plastic pipe 

Prohibited devices in 7.10 

Prohibited locations 7.2.5, A.7.2.5 

Protection, underground piping 7.1.2 

Protective coating 5.6.2.5, 5.6.3.3, 5.6.6 

Removal of 7.2.7 

Sediment traps 9.6.7 

Sizing and capacities of 5.4.1, 5.4.3, Chap. 6, 9.1.16, Chap. 13, 

A.5.4.1,A.5.4.3, Annex C 

Equations 6.4, A.6.4.1, A.6.4.2, C.5, C.6 

Examples C.8 

Methods 6.1, A.6.1.1, A.6.1.2, C.4, C.8 

Modification to existing system C.8.4 

Overpressure relief devices 5.9.8 

Sizing charts, use of C.7 

Sloped 7.2.3,7.2.4 

Strain on 9.1 .17 

Supports see Supports, Pipes and piping 

Turns 7.5 

Underground 7.1, A.7.1.3, A.7.1.4 

Used materials 5.6.1.2 

Valves 7.9 

In vertical chases 7.4, A.7.4.3 

Workmanship 5.6.5 

Pipe threads, metallic 5.6.2.4, 5.6.7, Table 5.6.7.3; see also Thread 

joint compounds 

Piping systems, gas Chap. 5 

Addition to existing 5.1.2 

Definition 3.3.98.6 

Design pressure 

Allowable pressure drop 5.4.1, 5.4.4, A.5.4.1, C.7(4) 

Maximum 5.5.1, A5. 5. 1(1) 

Flexibility 5.13 

Gas-air mixtures 

Flammable 7.12, A.7.12.4 to A.7.12.6(l) 

Outside the flammable range 7.11 

Interconnections between 5.3 

Leakage tests 8.1.5, 8.2, A.8.2.3 

Local conditions, consideration of 5.13.2 

Materials and joining methods 5.6, A.5.6.2.3 to A.5.6.8.1 

Operating pressure limitations 5.5, A.5.5.1(l) 

Placing in operation, purging for 8.3.2 

Plan 5.1 

Point of delivery, location of 5.2 

Pressure drop, allowable 5.4.1, 5.4.4, A.5.4.1, C.7(4) 

Pressure testing and inspection 8.1, A.8. 1.4.3 

Purging 8.3, Table 8.3.1, Table 8.3.2, A.8.3 

Removal from service, purging for 8.3.1 

Sizing of .... 5.4, 6.2, 6.3, Tables 6.2(a) to 6.2 (v), A.5.4.1 toA.5.4.3, 

Annex C, Tables 6.3(a) to 6.3(m) 
Thermal expansion 5.13 



2006 Edition 



ANSIZ223.1-159 



INDEX 



54-159 



Plastic pipe 5.6.4, 5.6.9, A.5.6.4.2 

Within chimney flue 12.6.8 

Connection of 7.1.7.1,7.1.7.2 

Sizing Table 6.2(r) to (v); Table 6.3 (k) to (m) 

Tracer wire to locate 7.1.7.3 

Turns 7.5.2 

As vent material 12.5.2 

Plenums (definition) 3.3.78; see also Furnace plenums 

Point of delivery, location of 5.2 

Pool heaters 10.21 

Definition 3.3.55.4 

Power, continuous 9.7.4 

Power burners see Burners 

Pressure 

Atmospheric (definition) 3.3.79.1 

Back 

Definition 3.3.79.2 

Protection 5.10 

Definition 3.3.79 

Design see Design pressure 

High pressure gas pipe sizing 

Formula 6.4.2, A.6.4.2, C.5(l) 

Sizing charts, use of C.7(6), Fig. C.7(b) 

Tables C.3.5 

Hybrid pressure pipe sizing method 6.1.3 

Low pressure gas pipe sizing 

Formula for 6.4.1, A.6.4.1, C.5(2) 

Sizing charts, use of C.7(5), Fig. C.7(a) 

Tables C.3.2 

Low-pressure protection 5.11 

Maximum working 

Definition 3.3.79.4 

Overpressure relief device and 5.9.5 

Operating, limitations on 5.5, A.5.5.1(l) 

Pressure drop per 100 ft. pipe sizing method C.4.4 

Pressure control (definition) K.1.34 

Pressure drop 

Allowable 5.4.1, 5.4.4, A.5.4.1, C.7(4) 

Definition 3.3.80 

Temperature change, calculating drop due to C.8.5 

Pressure limiting devices 10.3.4, 10.21.3, 10.28.3 

Definition 3.3.28.2 

Pressure regulators see Overpressure protection devices; 

Regulators 

Pressure relief devices 10.3.6, 11.5, A.10.3.6; see also Overpressure 

protection devices 

Water heaters 10.28.5 

Pressure relief valves see Valves, Pressure relief 

Pressure tests 8. 1 , A.8. 1.4.3 

Definition 3.3.81 

Primary air 11.2, A.ll .2 

Definition 3.3.2.4 

Process air 9.1 .7 

Protection see also Corrosion, protection against; Overpressure 

protection devices 
Appliances and equipment 

Floor furnaces 10.11. 10 

From fumes or gases 9.1.6, A.9. 1.6 

Open-top broiler units 10.19.3 

Outdoor appliances 9. 1 .23 

Physical 9.1.13,9.6.1(7) 

Pool heaters 10.21.1 

Back pressure 5.10 

Control piping 5.9.4 

Equipment 9. 1 .23 

Gas pressure regulators 5.8.4 

Low-pressure 5.11 

Meters, gas 5.7.4 

Piping, underground 7.1 .2 

Protective devices 11.5 



Purge/purging 8.3, Table 8.3.1, Table 8.3.2, 10.8.8, 10.9.8, A.8.3 

Definition 3.3.82 

Q- 

Qualified agency 4.1 

Definition 3.3.83 

Quick-disconnect devices 7.7.1.6, 7.7.2.1 Ex. 2, 9.6.5 

Definition 3.3.28.3 

-R- 

Kadianl appliances see Decorative appliances, to install in vented 

fireplaces 

Ranges see Food service appliances 

References Chap. 2, Annex L 

Refrigeration systems 

Boilers used with 10.3.9 

Coils 10.3.8 

Duct furnaces used with 10.10.6 

Refrigerators (using gas fuel) 10.22 

Definition 3.3.85 

Venting 12.3.2(6) 

Regulations, gas supplier 1.1.2 

Regulators 

Appliance 9.1.18 

Adjustable (definition) K.1.35 

Definition 3.3.86.1 

Illuminating appliances 10.16.5 

Multistage (definition) K.1.36 

Nonadjustable (definition) K.1.37 

Venting of 9.1.19 

Appliance pressure 5.8.5.2 

Draft see Draft regulators 

Equipment 5.8.1, 5.8.3, 5.8.4 

Venting 5.8.5.2 

Line gas 5.8.1 to 5.8.5 

By-pass piping 5.8.6 

Definition 3.3.86.3 

Identification 5.8.7 

Venting 5.8.5.1 

Monitoring (definition) 3.3.86.4 

Pressure 5.8, 7.4.1, 9.1.18, A.5. 8; see also Overpressure 

protection devices; subhead: Appliance 

Definition 3.3.86.5 

Gas shutoff valves at 7.9. 1 

Venting of 9.1.19 

Protection of 5.8.4 

Series (definition) 3.3.86.6 

Service (definition) 3.3.86.7 

Regulator vents 5.6.4.2, A.5.6.4.2 

Definition 3.3.105.3 

Relief openings 

Definition 3.3.87 

Industrial air heaters 10.8.7, 10.9.7 

Relief valves see Valves, Relief 

Repairs, gas shutoff prior to 4.2.2 

Residential board and care occupancy (definition) 3.3.71.2 

Retroactivity of code 1.3 

Risers 

Anodeless see Anodeless risers 

Corrosion, protection against 7.3.5.2 

Roofs 

Appliances on 9.4 

Piping on 7.2.6.4 

Room heaters 10.23, A.10.23.1 

Institutions, installations in 10.23.2 

Prohibited installations 10.23. 1 , A.10.23. 1 

Unvented 10.23.1, 12.3.2(8), A.10.23.1 

Closed front wall heater (definition) K.1.43 

Definition 3.3.55.6 

Unvented circulator (definition) K.1.38 

Vented 

Definiuon Kl .39 

Overhead heater (definition) K. 1 .42 



2006 Edition 



54-160 



NATIONAL FUEL GAS CODE 



ANSI Z223.1-160 



Vented circulator 

Definition K.1.40 

Fan type (definition) K.1.41 

Wall 10.23.4 

Unvented closed front (definition) K.1.43 

Room large in comparison with size of appliance (definition) . . . 3.3.88 



-S- 
Safety blowouts (backfire preventers) ... 7.12.1(4), 7.12.6, A.7.12.6(l) 

Definition 3.3.89 

Safety inspection, existing appliance installation Annex H 

Safety shutoff devices 10.4.6, 11.3; see also Valves, Appliance 

shutoff 

Definition 3.3.28.4 

Unlisted LP-gas equipment used indoors 9.1.4 

Scope of code 1.1 

Screens, protecting openings 9.3.7.1, 9.3.7.2 

Seepage pan 10.11 .9 

Separate users, interconnections between 5.3.1 

Service head adapters (definition) 3.3.90 

Service meter assembly (definition) 3.3.91 

Service regulators (definition) 3.3.86.7; see also Regulators, 

Pressure 

Service shutoff valves see Valves 

Shall (definition) 3.2.5 

Shutoff procedure 4.2.1; see also Safety shutoff devices; Valves 

Shutoff valves see Valves 

Sources of ignition see Ignition, Sources 

Spaces 

Surrounding chimney lining or vent 12.6.8 

Well-ventilated 12.3.4 

Specific gravity 

Definition 3.3.94 

Fixed orifices, flow of gas through Annex F 

Sizing of gas pipe and C.3.4 

Standby fuels, interconnections for 5.3.2 

Steam cookers see Food service appliances 

Steam generators see Food service appliances 

Stress 

Definition 3.3.97 

Hoop (definition) 3.3.97.1 

Structural members, building 9. 1 .8 

Supports 

Chimneys 12.6.6 

Equipment 9.1.8.3 

Floor furnaces 10.11.6 

Gas vents 12.7.5 

Heaters, infrared 10.18.1 

Meters, gas 5.7.3 

Pipes and piping 5.13.2, 7.2.1, 7.2.6, Table 7.2.6.2 

Single-wall metallic pipe 12.8.6 

Vent connectors 12.11.10 

Suspended-type unit heaters 10.26.2.1 

Switches, electrical supply line 10.2.7 

Systems see also Central premix system; Fan-assisted combustion 

system; Hybrid pressure system; Mechanical exhaust 
systems; Piping systems, gas; Venting systems 
Natural draft venting systems (definition) 3.3.98.5 



Temperature change, calculating pressure drop due to C.8.5 

Temperature limit controls/devices 10.3.4 

Floor furnaces 10.11.2 

Pool heaters 10.21.3 

Water heaters 10.28.4 

Temperature relief valves see Valves, Temperature relief 

Tensile strength (definition) 3.3.99 

Termination, venting systems see Venting systems 

Testing, piping system 

Defects, pressure test for 8.1.5 



Leakage 

Pressure test for detection 8.1.5 

System and equipment test 8.2, A.8.2.3 

Pressure 8.1, A.8.1 .4.3 

Definition 3.3.81 

Thermostats 

Electric switch type (definition) 3.3.100.1 

Integral gas valve type (definition) 3.3.100.2 

Room temperature 9.8 

Thimbles 12.8.4.5, 12.11.14.2 

Thread joint compounds 5.6.7.4 

Definition 3.3.101 

ToUets, gas-fired 10.25, Table 12.5.1, Table 12.8.4.4 

Traps, sediment 9.6.7 

Trenches 7.1.2.2 

Tubing 

Appliances and equipment connections 9.5.1(2), 9.6.1(7) 

Connections 7.3.2 

Definition 3.3.102 

Low pressure gas pipe sizing tables C.3.2 

Metallic 5.6.3, 5.6.8.2, A.5.6.3.2 

Partitions, in 7.3.4 

Plastic 5.6.4, 5.6.9, A.5.6.4.2 

Sizing and capacities of Tables 6.2(f) to (q), Table 6.2 (u), 

Table 6.2(v), Table 6.3(m), Tables 6.3(e) to (j), C.6, 
Table C.6(b), C.8.3 

Workmanship and defects 5.6.5 

Type B gas vents see Gas vents 

Type B-W gas vents see Gas vents 

Type L vents see Gas vents 



-U- 

Underground piping 7.1, A.7.1.3, A.7.1.4 

Unit broilers 

Definition 3.3.14.1 

Open-top 10.19 

Unit heaters 10.26 

High-static pressure type (definition) 3.3.55.5.1 

Low-static pressure type (definition) 3.3.55.5.2 

Utility gases 

Definition 3.3.50.2 

Fixed orifices, flow of gas through Annex F 



-V- 

Vacuum relief valves see Valves, Vacuum relief 

Valve members 

Definition 3.3.104 

Nondisplaceable (definition) 3.3.104.1 

Valves 

Accessibility of 7.9.2.1 

Appliance shutoff 5.12, 7.7.2.2, 9.6.4, 12.6.5.2 

Definition 3.3.103.1 

Gas-mixing machines 7.12.5.4, A.7.12.5.4 

Manual 7.9 

Automatic (definition) 3.3.103.2 

Automatic gas shutoff (definition) K.1 .44 

Bypass see Bypass valves 

Controlling multiple systems 7.9.2 

Definition 3.3.103 

Diaphragm type, bleed lines for 9.1.20 

Individual main burner (definition) K.1.45 

Main burner control (definition) K.1.46 

Manual main gas control 7.9.2. 1 

Definition K.l .47 

Manual reset 7.12.5.4, A.7.12.5.4 

Definition 3.3.103.3 

Mixing blowers 7.12.4, A.7.12.4 

Pressure relief 

Definition 3.3.103.4.1 

For steam and hot water boilers 10.3.6, A.10.3.6 



2006 Edition 



ANSIZ223.1-161 



INDEX 



54-161 



Relief (definition) 3.3.103.4 

Service shutoff 5.12 

Definition 3.3.103.5 

Emergency 7.9.2.3 

Manual 7.9, 9.6.4 

For multiple systems 7.9.2 

Temperature relief 10.28.5 

Definition 3.3.103.4.2 

Used 5.6.1.2 

Vacuum relief 10.28.5 

Definition 3.3.103.4.3 

Vapors, flammable, appliances in area of 9.1.9 

Vehicular fuel systems, compressed natural gas 10.29 

Vent(s) 

Common see Common Vents 

Definition 3.3.105 

Gas see Gas vents 

Heater 10.8.6,10.9.6 

Obstructions 12.16, 13.1.1 

Offset 13.2.5 

Definition 3.3. 107 

Overpressure protection devices 5.9.7 

Regulator 5.6.4.2, A.5.6.4.2 

Definition 3.3.105.3 

Sizes 

Appliance categorized vent diameter/area (definition) . . . 3.3.7 

Multiple appliance vents 13.2, Tables 13.2(a) to (h), 

A.13.2.20 

Single appliance vents 13.1, Tables 13.1(a) to (e),A.13.1.7 

Toilets, gas-fired 10.25.3 

Vent connectors 12.11, 12.12, A.12. 11.3 

Bends 12.10.6 

Chimneys see Chimneys 

Clearance 12.11 .5 

Dampers 12.14, 12.15 

Definition 3.3.106 

Fireplaces 12.11.13 

Inspection 12.11.12 

Joints 12.11.7 

Length 12.11.9 

Location 12.11.11 

Materials 12.11.2, Table 12.11.2.5, Table 12.11.2.6 

Maximum length 13.2.2, Table 13.2.2, 13.2.3 

Mechanical draft systems 12.4.3.4 

Obstructions 12.16 

Routing Table 13.2.2, 13.2.3 

Size of 12.11.3, 13.1.12, 13.1.13, 13.2.4, 13.2.8, A.12.11.3 

Slope 12.11.8 

Support 12.11.10 

Through ceilings, floors, or walls 12.11.14 

Toilets, gas-fired 10.25.3 

Two or more appliances 12.11.3.3 to 12.11.3.6, 12.11.4 

Vent damper device, automatic 12.14; see also Dampers 

Definition 3.3.28.5.1 

Electrically operated (definition) 3.3.28.5.2 

Mechanically operated (definition) 3.3.28.5.3 

Thermally actuated (definition) 3.3.28.5.4 

Vented appliances 

Categoryl Table 12.5.1, 12.6.1.3 Ex., 12.6.3.1, 12.7.1(3), 

12.7.3.1, 12.10.2, 12.11, 13.1.10, Chap. 13, A.12.10.3, 
Annex G 

Definition 3.3.6.11.1, A.3.3.6.11.1 

Category II Table 12.5.1, 12.9.4, 12.10.1 

Definition 3.3.6.11.2 

Category III Table 12.5.1, 12.9.4, 12.10.2 

Definition 3.3.6.11.3 

Category IV Table 12.5.1, 12.9.4, 12.10.1 

Definition 3.3.6.11.4 

Vented wall furnaces 10.27.1.3, 10.27.1.4, Table 12.5.1 

Definition 3.3.46.7 

Fan-type (definition) K.1.48 

Gravity-type (definition) K.1.49 



Vent gases (definition) 3.3.50.3 

Ventilating hoods 10.19.3, 12.3.3, 12.4.4, 12.7.2(1) (g), A.12.3.3, 

A.12.4.4 
Ventilation 

Air for 9.3, A.9.3 

Opening design, example of Annex J 

Chase 7.4.3, A.7.4.3 

Equipment 9.1.2(1) 

Food service appliances 10.12.8, A.10. 12. 8 

Industrial air heaters 10.8.3.3, 10.8.5, 10.9.5 

Infrared heaters 10.18.3 

Open-top broiler units 10.19.3, 10.19.4 

Venting Chap. 12 

Definition 3.3.108 

Equipment not requiring venting 1 2.3.2 

Flue gases 9.1.14 

Pressure regulators 5.8.5, 7.4.1, 9.1.19 

Venting systems 

Appliances 9.1.14 

Connection to see Vent connectors 

Definition 3.3.98.7, A.3.3.98.6 

Design and construction 12.4, A.12.4.4 

Equipment 9.1 .2(3) 

Mechanical draft 

Definition 3.3.98.7.2 

Forced (definition) 3.3.98.7.1 

Induced (definition) K.1.50 

Power (definition) K.1.51 

Natural draft (definition) 3.3.98.5 

Pool heaters 10.21 .5 

Refrigerators 10.22.2 

Sizing of 

Appliances equipped with draft hoods or listed for use with 

Type B vent Annex G 

Category I appliances 12.6.3.1, Chap. 13, Annex G 

Specification for 12.3, A.12.3.3 

Termination 

Chimneys 12.6.2 

Gas vents 12.7.2 

Mechanical draft systems 12.4.3.6 

Single-wall metal pipe 12.8.3 

Through the wall 12.9, Fig. A.12.9 

Two or more appliances, single vent 12.11.3.3 to 12.11.3.6, 

12.11.4, 13.2.18 

Type of system to use 12.5, Table 12.5.1 

Vented appliances see Vented appliances 

-w- 

Wall furnaces 10.27 

Direct vent (definition) 3.3.46.2 

Vented see Vented wall furnaces 

Wall head adapter (definition) 3.3.109 

Wall room heaters 10.22.4 

Unvented closed front (definition) K.1.43 

Water heaters 10.28, A.10.28.7 

Anti-siphon devices 10.28.7, A.10.28.7 

Automatic circulating tank (definition) K.1.52 

Automatic instantaneous type 10.28.6 

Definition K.1.53 

Circulating tank type 10.28.7, A.10.28.7 

Coil circulation (definition) K.1.54 

Commercial storage (definition) K.1.55 

Countertop domestic storage (definition) K.1.56 

Definition 3.3.55.7 

Domestic storage (definition) K.1.57 

Nonautomatic circulating tank (definition) K.1.58 

Venting 12.3.2(5), 13.1.11(5), G.2.1 to G.2.4 

Weather conditions 5.13.2, 7.2.3 

Floor furnaces and 10.11.10 

Protection against 7.1.4, A.7.1.4 

Single-wall metal pipe, use of 12.8.2, A.12.8.2 

Work interruptions 4.2.2 



Cou/W 



3 4 5 6 



08 07 



2006 Edition 



Sequence of Events Leading to Publication 
of an NFPA Committee Document 

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Report — Report on Proposals (ROP) — is published for public 
review and comment 



Committee meets to act on each public comment received. 



Committee votes on comments by letter ballot If two-thirds 

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NOTE 1: "Standard" connotes code, standard, recommended 
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NOTE 2: A representative includes an employee. 

NOTE 3: While these classifications will be used by die Stan- 
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9/99A 



FORM FOR PROPOSALS ON NFPA TECHNICAL COMMITTEE DOCUMENTS 



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